Dilution Modeling: Forecast Founder Ownership Through Series C (2025 Guide)

What is Dilution Modeling?

Dilution modeling is the process of forecasting how your ownership percentage will change as your startup raises funding and issues new shares.

What Causes Dilution?

Every time your company issues new shares, existing shareholders own a smaller percentage of the company (even though they own the same number of shares).

Dilution events:

  1. Option pool creation/refresh (reserve shares for employees)
  2. Fundraising (SAFEs, convertible notes, priced equity rounds)
  3. Stock option exercises (employees exercise options → new shares issued)
  4. Advisor/board member grants (issue restricted stock or options)

Why Model Dilution?

For founders:

  • Know what % you'll own after Series A, B, C
  • Plan for minimum ownership target (e.g., "I want to own >20% at exit")
  • Negotiate better terms (minimize dilution per round)

For employees:

  • Understand value of stock options (e.g., "0.1% seems small, but company is raising $100M at $1B valuation")
  • Model payout at exit (e.g., "If company sells for $500M and I own 0.05%, I get $250K")

For investors:

  • Model returns based on ownership % (e.g., "We'll own 20% post-Series A, need $200M exit for 5x return")

Why Dilution Modeling Matters

Scenario 1: Founder Dilution from 100% to 15%

Typical dilution path (Seed → Series C):

Stage Founder Ownership Cumulative Dilution
Incorporation 50% (each founder) 0%
+Option pool (15%) 42.5% 7.5%
SAFE ($500K @ $10M cap) 40.4% 2.1%
Seed ($2M @ $10M post) 32.3% 8.1%
+Option refresh (+5%) 30.7% 1.6%
Series A ($8M @ $32M post) 24.6% 6.1%
+Option refresh (+4%) 23.6% 1.0%
Series B ($20M @ $100M post) 18.9% 4.7%
+Option refresh (+3%) 18.3% 0.6%
Series C ($40M @ $200M post) 14.6% 3.7%

Total dilution: 50% → 14.6% (70.8% cumulative dilution)

Key insight: Each founder goes from 50% at incorporation to ~15% by Series C. This is normal for venture-backed startups.

Scenario 2: Employee Ownership is Worth More Than You Think

Employee receives 0.1% equity grant at Series A.

At Series A: 0.1% feels small ("I only own 0.1%?")

By Series C:

  • Company raised Series B ($100M post), Series C ($200M post)
  • Employee diluted to 0.08% (from 0.1%)
  • But company is now worth $200M (vs $32M at Series A)

Value at Series A: 0.1% × $32M = $32,000 Value at Series C: 0.08% × $200M = $160,000

5x increase in value, despite 20% dilution.

Scenario 3: Raising Too Much Too Early

Founder raises $10M seed round at $20M post-money (50% dilution).

Seems like a win (lots of capital), but:

  • Founder owns 50% immediately (vs 85-90% typical after seed)
  • By Series B, founder owns <20% (vs ~30% typical)
  • Founder loses control (board seats, decision-making)
  • Harder to motivate with equity (too diluted too early)

Better approach: Raise $2M seed at $10M post (20% dilution), then $8M Series A at $32M post (25% dilution).

  • Total dilution: ~40% (vs 50% with mega-seed)
  • Founder owns 30-35% after Series A (vs 25% with mega-seed)

Types of Dilution

1. Option Pool Dilution

When: Creating or expanding employee stock option pool.

Who gets diluted: Founders and existing shareholders (investors if post-money pool, but rare).

Typical dilution:

  • At incorporation: 10-15% option pool (founders diluted 10-15%)
  • At Series A: 5-10% option pool refresh (everyone diluted 5-10%)
  • At Series B+: 3-5% refresh (everyone diluted 3-5%)

Formula:

Option Pool Shares = Pool % / (1 - Pool %) × Existing Shares
New Ownership % = Your Shares / (Existing Shares + Pool Shares)

Example:

Founders own 10M shares (100%). Create 15% option pool.

Pool Shares = 15% / (1 - 15%) × 10,000,000 = 1,764,706 shares
Founder A Ownership = 5,000,000 / 11,764,706 = 42.5%

Founder A diluted from 50% to 42.5% (7.5% dilution).

2. Investment Dilution

When: Issuing preferred stock to investors (Series Seed, A, B, C).

Who gets diluted: All existing shareholders proportionally.

Typical dilution:

  • Seed: 15-25% to investor
  • Series A: 20-25% to investor
  • Series B: 15-20% to investor
  • Series C: 10-15% to investor

Formula:

Investor Shares = Investment / Price per Share
New Ownership % = Your Shares / (Existing Shares + Investor Shares)

Or, using post-money valuation:

Investor % = Investment / Post-Money Valuation
Your New % = Your Old % × (1 - Investor %)

Example:

Founder owns 42.5% (5M of 11.76M shares). Series A: $8M at $32M post (25% to investor).

Founder New % = 42.5% × (1 - 25%) = 31.9%

Founder diluted from 42.5% to 31.9% (10.6% dilution).

3. SAFE / Convertible Note Dilution

When: SAFEs or convertible notes convert to equity at priced round.

Who gets diluted: All existing shareholders proportionally.

Typical dilution: 5-15% (depends on amount raised, valuation cap).

Formula:

SAFE converts at the lower of:

  1. Valuation cap
  2. Discount on Series A price (typically 20%)
SAFE Ownership % = SAFE Investment / Valuation Cap (or Discount Price)
Your New % = Your Old % × (1 - SAFE %)

Example:

Outstanding SAFE: $500K at $10M cap. Series A: $8M at $32M post-money.

SAFE % = $500K / $10M = 5% of pre-SAFE cap table

If pre-SAFE cap table was 11.76M shares:
SAFE shares = 5% / (1 - 5%) × 11.76M = 618,947 shares
New total: 12,378,947 shares

Founder ownership = 5,000,000 / 12,378,947 = 40.4%

Founder diluted from 42.5% to 40.4% (2.1% dilution from SAFE conversion).

4. Employee Exercise Dilution

When: Employees exercise stock options.

Who gets diluted: All existing shareholders proportionally.

Typical dilution: 1-3% per year (as employees vest and exercise).

Note: This dilution is already accounted for in "fully diluted" ownership calculations (since option pool is included in fully diluted share count).

Dilution Benchmarks by Stage (2025 Data)

Seed Round Dilution

2025 benchmark: 19% median dilution (down from 20-25% in 2019-2021)

Typical range:

  • Conservative: 15-18% (strong founders, competitive term sheets)
  • Standard: 18-22%
  • Aggressive: 22-30% (first-time founders, less competitive)

Why declining?

  • More founder-friendly terms (post-money SAFEs, smaller rounds)
  • Better negotiating leverage (more seed funds competing)

Series A Dilution

2025 benchmark: 20-25% dilution

Typical range:

  • Strong companies: 18-22%
  • Standard: 20-25%
  • Struggling companies: 25-30% (down round, investor demands more equity)

Option pool refresh adds 5-10% dilution (on top of 20-25% to investor).

Series B Dilution

2025 benchmark: 15-20% dilution

Typical range:

  • Strong growth: 12-18%
  • Standard: 15-20%
  • Slower growth: 20-25%

Option pool refresh adds 3-5% dilution.

Series C+ Dilution

2025 benchmark: 10-15% dilution per round

Typical range:

  • Unicorn trajectory: 8-12%
  • Standard growth: 10-15%
  • Slow growth: 15-20%

Option pool refresh adds 2-4% dilution.

Cumulative Dilution: Seed to Series C

Median cumulative dilution:

Metric Seed Series A Series B Series C
Median dilution (this round) 19% 22% 17% 12%
Cumulative dilution (from 100%) 19% 37% 48% 54%
Founder ownership (each, from 50%) 40.5% 31.5% 26.0% 23.0%

Source: Carta 2024-2025 dilution data, Rebel Fund analysis

Key insight: Founders typically own 20-25% by Series C (started at 50% each).

How to Calculate Dilution

Formula 1: Simple Dilution from Investment

Given:

  • Your current ownership: X%
  • New investment: Y% of post-money goes to investor

Your new ownership:

New Ownership % = Old Ownership % × (1 - Investment %)

Example:

You own 40%. Investor gets 25% (Series A).

New % = 40% × (1 - 25%) = 40% × 75% = 30%

You're diluted from 40% to 30% (10 percentage points, 25% dilution ratio).

Formula 2: Dilution from Share Issuance

Given:

  • Your shares: A
  • Existing total shares: B
  • New shares issued: C

Your new ownership:

New Ownership % = A / (B + C)
Old Ownership % = A / B
Dilution = Old % - New %

Example:

You own 5M shares out of 12M (41.67%). Investor buys 4M shares (Series A).

New % = 5,000,000 / (12,000,000 + 4,000,000) = 31.25%
Dilution = 41.67% - 31.25% = 10.42 percentage points

Formula 3: Dilution Percentage (Ratio)

Dilution ratio = (Old % - New %) / Old %

Dilution Ratio = (Old % - New %) / Old %

Example:

Diluted from 40% to 30%.

Dilution Ratio = (40% - 30%) / 40% = 25%

You've been diluted by 25% (lost 1/4 of your ownership percentage).

Modeling Dilution from Incorporation to Series C

Full Dilution Model: Seed to Series C

Starting point:

  • 2 founders, 5M shares each (10M total)
  • Each founder owns 50%

Step 1: Create Option Pool (15%)

Pool Shares = 15% / (1 - 15%) × 10,000,000 = 1,764,706 shares
Fully Diluted = 11,764,706 shares

Founder A: 5,000,000 / 11,764,706 = 42.5%

Dilution: 50% → 42.5% (7.5% dilution)

Step 2: SAFE Conversion ($500K @ $10M cap)

SAFE % = $500K / $10M = 5% of pre-SAFE shares

SAFE Shares = 5% / (1 - 5%) × 11,764,706 = 618,668 shares
Fully Diluted = 12,383,374 shares

Founder A: 5,000,000 / 12,383,374 = 40.4%

Dilution: 42.5% → 40.4% (2.1% dilution)

Step 3: Seed Round ($2M @ $10M post-money, 20% to investor)

Investor Shares = 20% / (1 - 20%) × 12,383,374 = 3,095,844 shares
Fully Diluted = 15,479,218 shares

Founder A: 5,000,000 / 15,479,218 = 32.3%

Dilution: 40.4% → 32.3% (8.1% dilution)

Step 4: Option Pool Refresh (+5% to 18% total ungranted)

After seed, option pool is ~10% of fully diluted (diluted by seed round). Need to refresh to 18% ungranted.

Currently: ~8% ungranted (some granted to early employees) Need: 18% ungranted Refresh: +10%

Refresh Shares = 10% / (1 - 10%) × 15,479,218 = 1,719,913 shares
Fully Diluted = 17,199,131 shares

Founder A: 5,000,000 / 17,199,131 = 29.1%

Dilution: 32.3% → 29.1% (3.2% dilution)

Step 5: Series A ($8M @ $32M post-money, 25% to investor)

Pre-money = $32M - $8M = $24M
Price per share = $24M / 17,199,131 = $1.395 per share
Investor Shares = $8M / $1.395 = 5,733,710 shares
Fully Diluted = 22,932,841 shares

Founder A: 5,000,000 / 22,932,841 = 21.8%

Dilution: 29.1% → 21.8% (7.3% dilution)

Step 6: Option Pool Refresh (+3% to 15% ungranted)

Refresh Shares = 3% / (1 - 3%) × 22,932,841 = 709,470 shares
Fully Diluted = 23,642,311 shares

Founder A: 5,000,000 / 23,642,311 = 21.1%

Dilution: 21.8% → 21.1% (0.7% dilution)

Step 7: Series B ($20M @ $100M post-money, 20% to investor)

Investor Shares = 20% / (1 - 20%) × 23,642,311 = 5,910,578 shares
Fully Diluted = 29,552,889 shares

Founder A: 5,000,000 / 29,552,889 = 16.9%

Dilution: 21.1% → 16.9% (4.2% dilution)

Step 8: Option Pool Refresh (+2% to 12% ungranted)

Refresh Shares = 2% / (1 - 2%) × 29,552,889 = 603,121 shares
Fully Diluted = 30,156,010 shares

Founder A: 5,000,000 / 30,156,010 = 16.6%

Dilution: 16.9% → 16.6% (0.3% dilution)

Step 9: Series C ($40M @ $200M post-money, 20% to investor)

Investor Shares = 20% / (1 - 20%) × 30,156,010 = 7,539,003 shares
Fully Diluted = 37,695,013 shares

Founder A: 5,000,000 / 37,695,013 = 13.3%

Dilution: 16.6% → 13.3% (3.3% dilution)

Summary: Founder A Dilution Journey

Stage Founder A % Dilution (This Round) Cumulative Dilution
Incorporation 50.0% — 0%
Option pool (15%) 42.5% 7.5% 7.5%
SAFE ($500K) 40.4% 2.1% 9.6%
Seed ($2M) 32.3% 8.1% 17.7%
Option refresh (+10%) 29.1% 3.2% 20.9%
Series A ($8M) 21.8% 7.3% 28.2%
Option refresh (+3%) 21.1% 0.7% 28.9%
Series B ($20M) 16.9% 4.2% 33.1%
Option refresh (+2%) 16.6% 0.3% 33.4%
Series C ($40M) 13.3% 3.3% 36.7%

Final: Founder A owns 13.3% (started at 50%, diluted 73.4% cumulative).

Company valuation journey:

  • Incorporation: $0
  • Seed: $10M post-money
  • Series A: $32M post-money
  • Series B: $100M post-money
  • Series C: $200M post-money

Founder A equity value:

  • Seed: 32.3% × $10M = $3.23M
  • Series A: 21.8% × $32M = $6.98M
  • Series B: 16.9% × $100M = $16.9M
  • Series C: 13.3% × $200M = $26.6M

Key insight: Founder A's ownership % decreased 73%, but equity value increased from $0 to $26.6M (infinite return).

Option Pool Dilution Impact

Pre-Money Option Pool (Standard)

Option pool is created before investment → Dilutes founders, not investors.

Example:

Before Series A:

  • Founders: 10M shares (100%)

Series A term sheet:

  • Investment: $5M at $25M post-money (20% to investor)
  • Option pool: 15% post-money (pre-money to founders)

Step 1: Create 15% pool pre-money

Founders + Pool = 80% (investor will get 20%)
Founders = 65%, Pool = 15%

Pool Shares = (15% / 65%) × 10,000,000 = 2,307,692 shares
Pre-money total = 12,307,692 shares

Step 2: Issue investor shares (20% post-money)

Investor Shares = (20% / 80%) × 12,307,692 = 3,076,923 shares
Post-money total = 15,384,615 shares

Final ownership:

  • Founders: 10,000,000 / 15,384,615 = 65%
  • Option pool: 2,307,692 / 15,384,615 = 15%
  • Investor: 3,076,923 / 15,384,615 = 20%

Founders diluted from 100% to 65% (35% dilution).

Option Pool Refresh Impact

At each funding round, option pool typically needs refresh (5-10% added).

Dilution from refresh:

Round Pool Before Pool After Refresh Dilution to Everyone
Seed 15% 15% (new) 15% created 15% (founders only)
Series A 10% (diluted from Seed) 18% ungranted +8% refresh 8%
Series B 12% (diluted from A) 15% ungranted +3% refresh 3%
Series C 10% (diluted from B) 12% ungranted +2% refresh 2%

Total option pool dilution across all rounds: ~30-35% (combines creation + refreshes).

SAFE and Convertible Note Dilution

Post-Money SAFE (Standard Since 2018)

Post-money SAFE converts based on post-money valuation cap.

Formula:

SAFE Ownership % = SAFE Investment / Post-Money Valuation Cap

Example:

SAFE: $500K at $10M post-money cap Series A: $5M at $25M post-money

SAFE conversion:

SAFE % = $500K / $10M = 5% of post-money cap table (at time of SAFE)

If cap table at time of SAFE was 11.76M fully diluted shares:

Post-money shares (for SAFE calc) = 11.76M / (1 - 5%) = 12.38M shares
SAFE shares = 12.38M - 11.76M = 618,947 shares

SAFE investors own 5% post-SAFE conversion, before Series A.

Then Series A investor gets 20%, diluting everyone (including SAFE) proportionally.

Final:

  • SAFE: 5% × 80% = 4% (diluted by Series A)
  • Founders: Diluted by SAFE (5%) + Series A (20%) = 25% total dilution

Pre-Money SAFE (Legacy, Rarely Used)

Pre-money SAFE converts based on pre-money valuation cap.

Formula:

SAFE Ownership % = SAFE Investment / (Pre-Money Cap + All SAFEs/Notes)

More founder-friendly (SAFE investors dilute each other, not founders as much).

Example:

SAFE 1: $300K at $8M pre-money cap SAFE 2: $200K at $8M pre-money cap Total SAFEs: $500K

SAFE conversion at Series A:

SAFE 1 % = $300K / ($8M + $500K) = 3.53%
SAFE 2 % = $200K / ($8M + $500K) = 2.35%
Total SAFE %: 5.88%

SAFEs dilute each other (since denominator includes all SAFEs).

Convertible Note Dilution

Convertible note converts at Series A using:

  1. Discount (typically 20%) on Series A price per share, OR
  2. Valuation cap (whichever gives investor more shares)

Example:

Convertible note: $500K at $10M cap, 20% discount Series A: $5M at $25M post-money, price = $2.00/share

Option 1: Use discount

Discount price = $2.00 × 80% = $1.60 per share
Note shares = $500K / $1.60 = 312,500 shares

Option 2: Use cap

Cap price = $10M / (shares at cap) ≈ $0.85 per share (lower = better for investor)
Note shares = $500K / $0.85 = 588,235 shares

Investor chooses cap (gets more shares).

Note investors get 588K shares, Series A investors get 2.5M shares (at $2/share).

Dilution to founders: ~6-7% from note + 20% from Series A = 26-27% total.

How to Minimize Dilution

Strategy 1: Raise Less Capital

Every dollar raised = dilution.

Trade-off:

  • Less capital = less dilution (you own more %)
  • But: Less capital = slower growth, higher risk of failure

Best practice: Raise just enough to reach next milestone (12-24 months of runway).

Example:

Scenario A (raise more):

  • Raise $10M Series A at $30M post (33% dilution)
  • Own 40% → 27%

Scenario B (raise less):

  • Raise $5M Series A at $20M post (25% dilution)
  • Own 40% → 30%
  • 18 months later, raise $10M Series B at $60M post (17% dilution)
  • Own 30% → 25%

Scenario B result: Own 25% (vs 27% in Scenario A), but with more milestones hit = higher Series B valuation.

Better dilution trajectory (even though same total capital raised).

Strategy 2: Increase Valuation

Higher valuation = less dilution for same $ raised.

Example:

Raise $5M Series A:

Scenario A (low valuation):

  • $5M at $15M post-money (33% dilution)

Scenario B (high valuation):

  • $5M at $25M post-money (20% dilution)

13% less dilution by negotiating higher valuation.

How to increase valuation:

  • Hit revenue milestones before fundraising
  • Get multiple term sheets (create competition)
  • Demonstrate strong growth metrics (ARR, user growth)

Strategy 3: Use Revenue-Based Financing or Venture Debt

Revenue-based financing (RBF) and venture debt don't dilute equity.

Revenue-based financing:

  • Borrow $500K-$2M
  • Repay as % of monthly revenue (3-8% of revenue until 1.3-2x repaid)
  • No equity dilution
  • Cost: 30-100% interest (higher than traditional debt, but no dilution)

Venture debt:

  • Borrow $1M-$10M (typically 20-30% of last equity round raised)
  • Repay over 3-4 years with interest (8-12%)
  • Minimal equity dilution (lender gets warrants for 0.5-2% of company)
  • Cost: 8-12% interest + 0.5-2% warrants

When to use:

  • Have revenue (RBF requires $500K+ ARR typically)
  • Need bridge capital between equity rounds
  • Don't want to dilute in down market (low valuations)

Example:

Scenario A (equity):

  • Raise $2M bridge at $20M post (10% dilution)
  • Own 30% → 27%

Scenario B (venture debt):

  • Borrow $2M venture debt (no dilution, just 1% warrants)
  • Own 30% → 29.7% (0.3% dilution from warrants)

9.7% less dilution using debt instead of equity.

Strategy 4: Negotiate Smaller Option Pool

Option pool size is negotiable.

Investor asks for 20% pool → Negotiate to 15% → Save 5% dilution.

How to negotiate:

  • Provide detailed hiring plan (prove you only need 15%)
  • Request post-money option pool (dilutes everyone, not just founders)
  • Defer pool refresh to Series B (only refresh if you need it)

Example:

Scenario A (accept 20% pool):

  • Create 20% option pool pre-money
  • Founders diluted from 100% to 80%
  • After Series A (25% to investor), founders own 60%

Scenario B (negotiate to 15% pool):

  • Create 15% option pool pre-money
  • Founders diluted from 100% to 85%
  • After Series A (25% to investor), founders own 63.75%

3.75% less dilution by negotiating option pool size.

Strategy 5: Bootstrap Longer

Every month you bootstrap = less capital needed = less dilution.

Example:

Scenario A (raise seed early):

  • Raise $1M seed after 3 months (20% dilution)
  • Raise $5M Series A after 18 months (25% dilution)
  • Own 50% → 40% → 30%

Scenario B (bootstrap 12 months):

  • Bootstrap to $500K ARR (12 months)
  • Raise $3M Series A at $15M post (20% dilution)
  • Own 50% → 40%

10% less dilution by bootstrapping longer + raising less capital at higher valuation.

Trade-off: Bootstrapping is slower, riskier (no safety net).

Dilution Scenarios and Trade-Offs

Scenario 1: Raise Large Seed, Skip Series A

Strategy: Raise $5-10M seed round (instead of $1-2M seed + $8M Series A).

Pros:

  • ✅ One fundraise instead of two (less time/effort)
  • ✅ Longer runway (24-36 months vs 18 months)
  • ✅ Less near-term dilution (one round vs two)

Cons:

  • ❌ Higher total dilution (30-40% seed vs 20% seed + 25% A = 40% total)
  • ❌ Harder to raise large seed (fewer investors write $5-10M seed checks)
  • ❌ Down round risk (if you need Series A later at lower valuation)

When to use:

  • Strong team (investors trust you with large check)
  • Capital-intensive business (hardware, biotech, marketplace)
  • Plan to hit Series B metrics on seed capital (skip Series A entirely)

Scenario 2: Raise Smaller Rounds, More Frequently

Strategy: Raise $1M → $3M → $8M → $20M (vs $5M → $25M).

Pros:

  • ✅ Less dilution per round (15-20% vs 25-30%)
  • ✅ Validate progress at each stage (reduce risk)
  • ✅ Higher valuations if you hit milestones

Cons:

  • ❌ More fundraising cycles (time-consuming)
  • ❌ More investor updates, board meetings (overhead)
  • ❌ Higher cumulative dilution (4 rounds of 20% = 60% diluted vs 2 rounds of 30% = 51% diluted)

When to use:

  • First-time founder (investors want to see progress before large check)
  • High-risk business model (need to validate before scaling)
  • Competitive fundraising environment (can raise at increasing valuations)

Scenario 3: Use SAFEs, Delay Priced Round

Strategy: Raise $500K SAFE + $1M SAFE (instead of $1.5M seed round).

Pros:

  • ✅ Faster to close (SAFEs close in 1-2 weeks vs 6-8 weeks for priced round)
  • ✅ No board seat (SAFEs don't get board representation)
  • ✅ Lower legal fees ($5K vs $25-50K for Series Seed)

Cons:

  • ❌ Dilution is deferred (you don't know % dilution until Series A)
  • ❌ Stacking multiple SAFEs = high dilution at Series A (10-20% from SAFEs)
  • ❌ Valuation cap negotiation (investors want low cap, founders want high)

When to use:

  • Pre-revenue or early revenue ($0-$500K ARR)
  • Need to move fast (close capital in 2-4 weeks)
  • Plan to raise Series A within 12-18 months

Using Dilution Calculators

Free Online Dilution Calculators

1. Capboard Dilution Calculator

  • Model dilution from multiple funding rounds
  • Shows ownership % after each round
  • Free, no signup required

2. Carta Dilution Calculator (requires free account)

  • Full cap table software (not just calculator)
  • Model dilution + option pool + SAFE conversion
  • Generate cap table reports for investors

3. Neos Chronos Dilution Calculator

  • Simple single-round dilution calculator
  • Shows pre-money vs post-money impact
  • Free, no signup required

4. Dilution.io

  • Excel-based dilution model
  • Download and customize
  • Free

How to Use a Dilution Calculator

Step 1: Enter current cap table

  • Founder shares
  • Existing investor shares
  • Option pool size
  • Outstanding SAFEs/notes

Step 2: Model next funding round

  • Investment amount ($5M)
  • Post-money valuation ($25M)
  • Option pool refresh (5% added)

Step 3: Review output

  • Your new ownership %
  • Dilution % (this round)
  • Cumulative dilution (since incorporation)
  • Investor ownership %

Step 4: Model multiple scenarios

  • Scenario A: $5M at $20M post (25% dilution)
  • Scenario B: $5M at $30M post (17% dilution)
  • Compare outcomes

Building Your Own Dilution Model (Excel/Google Sheets)

Column headers:

Stage Round Size Post-Money Val Investor % Founder Shares Total Shares Founder % Dilution

Formulas:

Investor % = Investment / Post-Money Valuation
Founder New % = Founder Old % × (1 - Investor %)
Dilution = Founder Old % - Founder New %

Example rows:

Stage Round Size Post-Money Val Investor % Founder % (Before) Founder % (After) Dilution
Incorporation — — — 50% 50% 0%
Option pool 15% — — — 50% 42.5% 7.5%
Seed $2M $10M 20% 42.5% 34% 8.5%
Series A $8M $32M 25% 34% 25.5% 8.5%
Series B $20M $100M 20% 25.5% 20.4% 5.1%

Common Dilution Mistakes

Mistake 1: Not Modeling Dilution Before Fundraising

What happens:

  • Founder accepts term sheet ($5M at $20M post, 20% option pool)
  • Calculates: "I'm giving up 25%, so I'll own 75% × 40% = 30%"
  • Wrong! Forgot about 20% option pool (pre-money to founders)
  • Actually owns: 60% post-option pool × 75% post-investment = 45%... wait, that's not right either.

Let me recalculate properly:

If founders own 40% before Series A, and:

  • Create 20% option pool pre-money
  • Investor gets 25% post-money

Correct math:

  • Founders start at 40%
  • Create 20% pool: Everyone diluted by 20%, so founders own 40% × (1 - 20%/(100%-20%)) = 40% × (1 - 25%) = 30%
    • Actually: Pool dilutes everyone pre-investment, so founders own 40% / (100% + 25% pool/(100%-25%)) = messy

Easier formula:

  • Target post-investment: Investor 25%, Pool 20%, Founders 55%
  • Founders had 40%, now have 55% of post-money = founders gained? No, that's wrong.

Let me use the correct approach:

Correct approach: Use cap table calculator. Don't do mental math.

Fix: Always model dilution in spreadsheet or calculator before accepting term sheet.

Mistake 2: Raising at Too Low Valuation

What happens:

  • Founder raises $2M at $6M post-money (33% dilution)
  • Could have raised $2M at $10M post-money (20% dilution) with more traction

Fix: Hit milestones before fundraising (higher valuation = less dilution).

Mistake 3: Accepting Investor's Option Pool Size Without Negotiation

What happens:

  • Investor term sheet: "20% option pool"
  • Founder accepts without question
  • 20% pool dilutes founders unnecessarily (actual hiring plan only needs 12%)

Fix: Provide hiring plan, negotiate to 12-15% pool (save 5-8% dilution).

Mistake 4: Forgetting About SAFE Dilution

What happens:

  • Founder raises $1M in SAFEs at various caps ($8M, $10M, $12M)
  • Models Series A dilution as 25% (investor gets 25%)
  • Forgets: SAFEs will convert at Series A, adding 10-15% dilution
  • Total dilution: 25% (investor) + 12% (SAFEs) = 37% (much more than expected)

Fix: Model SAFE conversion at Series A (include in dilution forecast).

Mistake 5: Not Planning for Option Pool Refresh

What happens:

  • Create 15% option pool at seed
  • Model Series A dilution as 25% (investor only)
  • Forgets: Series A requires 10% option pool refresh
  • Total dilution: 25% (investor) + 10% (pool refresh) = 35%

Fix: Assume option pool refresh at each round (add 5-10% dilution).

Dilution Modeling Examples

Example 1: Conservative Dilution Path (SaaS Startup)

Strategy: Bootstrap longer, raise less capital, grow efficiently.

Stage Capital Raised Post-Money Val Founder % Cumulative Dilution
Incorporation — — 50% 0%
Option pool (10%) — — 45% 5%
Bootstrap to $1M ARR — — 45% 0%
Series A $5M $25M 36% 9%
Grow to $10M ARR — — 36% 0%
Series B $15M $100M 29% 7%
Grow to $50M ARR — — 29% 0%
Series C $30M $300M 24% 5%

Total capital raised: $50M Final founder ownership: 24% each (48% total) Company valuation: $300M Founder equity value: $72M each ($144M total)

Key insight: Efficient capital use = less dilution (24% vs 15% typical).

Example 2: Aggressive Dilution Path (Capital-Intensive Startup)

Strategy: Raise large rounds, grow fast, outpace competition.

Stage Capital Raised Post-Money Val Founder % Cumulative Dilution
Incorporation — — 50% 0%
Option pool (15%) — — 42.5% 7.5%
Seed $5M $15M 28.3% 14.2%
Series A $20M $60M 18.9% 9.4%
Series B $50M $200M 14.2% 4.7%
Series C $100M $600M 11.8% 2.4%

Total capital raised: $175M Final founder ownership: 11.8% each (23.6% total) Company valuation: $600M Founder equity value: $70.8M each ($141.6M total)

Key insight: More capital raised = more dilution (11.8% vs 24%), but higher absolute value ($600M vs $300M).

Example 3: Balanced Dilution Path (Standard VC-Backed)

Strategy: Raise standard rounds at market valuations.

Stage Capital Raised Post-Money Val Founder % Cumulative Dilution
Incorporation — — 50% 0%
Option pool (15%) — — 42.5% 7.5%
SAFEs $500K $10M cap 40% 2.5%
Seed $2M $10M 32% 8%
Series A $8M $32M 24% 8%
Series B $20M $100M 19.2% 4.8%
Series C $40M $250M 15.4% 3.8%

Total capital raised: $70.5M Final founder ownership: 15.4% each (30.8% total) Company valuation: $250M Founder equity value: $38.5M each ($77M total)

Key insight: Standard path = ~15-20% ownership by Series C (started at 50%).

FAQ

How much dilution should I expect per funding round?

Typical dilution:

  • Seed: 15-25% (median 19% in 2025)
  • Series A: 20-25%
  • Series B: 15-20%
  • Series C+: 10-15% per round

Plus option pool refresh adds 3-10% dilution at each round.

What percentage should founders own after Series A?

Typical founder ownership post-Series A: 25-35% (each founder, if 2 co-founders).

Breakdown:

  • Started at 50% each
  • Diluted by option pool (7.5%)
  • Diluted by SAFEs/seed (5-10%)
  • Diluted by Series A (8-12%)
  • End up with 25-35% each

How can I minimize dilution?

Top strategies:

  1. Raise less capital (only what you need for next 18-24 months)
  2. Increase valuation (hit milestones before fundraising)
  3. Use debt instead of equity (venture debt, RBF)
  4. Negotiate smaller option pool (provide hiring plan)
  5. Bootstrap longer (defer fundraising, reduce capital needs)

What is cumulative dilution?

Cumulative dilution = Total % ownership lost from incorporation to current stage.

Formula:

Cumulative Dilution = (Starting % - Current %) / Starting %

Example:

Started at 50%, now own 20%.

Cumulative Dilution = (50% - 20%) / 50% = 60%

You've lost 60% of your original ownership (through multiple rounds of dilution).

Is dilution bad?

Dilution is not inherently bad. It depends on the trade-off.

Good dilution:

  • Raise $10M at $50M post (20% dilution) → Build product → Company worth $500M
  • Your equity value increased 10x (despite 20% dilution)

Bad dilution:

  • Raise $10M at $20M post (50% dilution) → Burn cash → Company shuts down
  • Your equity value = $0

Key question: Is the capital you're raising worth the dilution?

How do I calculate my equity value after dilution?

Formula:

Equity Value = Ownership % × Post-Money Valuation

Example:

You own 25% after Series B ($100M post-money).

Equity Value = 25% × $100M = $25M

Your equity is worth $25M (if company sold today for $100M).

What ownership % should I target at exit?

Target: 10-20% ownership at exit (for each founder, if 2 co-founders).

Why:

  • Owning 15% of $500M company = $75M per founder
  • Owning 30% of $100M company = $30M per founder

Better to own smaller % of larger company (dilution for growth is worth it).

Can I model dilution in Excel?

Yes. Build simple dilution model:

Columns:

  • Stage
  • Capital Raised
  • Post-Money Valuation
  • Investor %
  • Your % (Before)
  • Your % (After)
  • Dilution

Formula:

Your % After = Your % Before × (1 - Investor %)

Or use free online calculators (Capboard, Carta, etc.).

Resources

Dilution Calculators

Data and Research

Guides

Related Guides

Get Help with Dilution Modeling

Understanding your dilution path is critical for making smart fundraising decisions. Too much dilution too early can leave you with <10% ownership at exit.

If you need help with:

  • Building dilution model (Seed through Series C)
  • Negotiating better terms (higher valuation, smaller option pool)
  • Comparing fundraising scenarios (equity vs debt, large vs small rounds)
  • Forecasting equity value at exit

Contact Promise Legal for a dilution modeling consultation.

Typical engagement:

  • Dilution forecast: $500-$1,500 (model 3-5 funding scenarios, forecast ownership through Series C)
  • Term sheet negotiation: $2,000-$5,000 (review term sheet, model dilution, negotiate better terms)
  • Cap table audit + dilution model: $2,000-$5,000 (clean up cap table, build dilution model, forecast future rounds)

This guide was last updated in January 2025. Dilution benchmarks, fundraising trends, and investor expectations may evolve over time. Consult with a startup attorney or financial advisor for advice specific to your company.

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