Startup Equity Calculator — Co-Founder Equity Split Tool

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    Equity Dilution Calculator

    Model dilution across funding rounds.

    See how cap table changes across pre-seed, seed and Series A — with option pool, SAFEs and founder retention.

    7,621 calculations4.8 ratingUpdated June 2026

    Equity Dilution Calculator — IdeaProof
    Live snapshot · Updated June 2026
    Standard Dilution
    Founders After
    64.0%Your stake
    Investors Get
    20.0%New equity
    Option Pool
    10.0%ESOP reserve
    Post-Money
    $2.50MValuation
    Cap table compositionTotal 100%
    Founders
    Investors
    ESOP
    Other
    Step 01

    Your equity workbench

    Visualize the cap table and tune every assumption — founder ownership updates instantly.

    Interactive equity dilution calculator with live cap table donut visualization.

    Cap Table

    Ownership distribution

    Founders

    64.0%

    Investors

    20.0%

    ESOP

    10.0%

    Other

    6.0%

    Comparison

    Before → After this round

    ShareholderBeforeAfterChange
    Founders
    80.0%64.0%
    -16.0%
    New Investors
    0.0%20.0%
    New
    Option Pool
    10.0%10.0%
    —
    Other
    10.0%6.0%
    -4.0%

    Before

    After

    Round parameters
    64.0%founders · post $2.5M

    This round

    $2.0M
    $
    $500K
    $

    Dilution 20.0% · Seed range (15–25%)

    Cap table before

    %
    %

    What this means

    For $500K you give up 20.0% · $25K/point

    At $50.0M exit your stake = $32.0M

    You keep voting control with 64.0%

    After Series A (~22% dilution) you'd hold ~49.9%

    Step 02

    Scenario comparison

    Compare four deal structures side-by-side and apply the one that protects your ownership.

    Compare

    Negotiation scenarios

    Current
    Now
    Pre-Money$2.0M
    Raise$500K
    Keep64.0%
    Dilution−20.0%
    Active
    Higher Valuation
    +50% valuation
    Pre-Money$3.0M
    Raise$500K
    Keep68.6%
    Dilution−14.3%
    Lower Raise
    −40% investment
    Pre-Money$2.0M
    Raise$300K
    Keep69.6%
    Dilution−13.0%
    Balanced
    Sweet spot
    Pre-Money$2.5M
    Raise$400K
    Keep69.0%
    Dilution−13.8%
    Step 03

    Advanced modeling

    Stress-test future rounds, exit scenarios and SAFE conversions before signing.

    Step 04

    Turn dilution into a deal

    Pre-fill your business plan with this cap table and brief investors with confidence.

    Next step

    Validate this round against your business plan

    We'll pull pre-money, raise size and dilution straight into your investor narrative.

    Founder's Playbook

    Equity Report

    Formula, June 2026 benchmarks, expert tips, mistakes and real cap-table case studies — all in one read.

    Equity dilution formula

    Investor % = Investment ÷ (Pre-Money + Investment)

    Step-by-Step Breakdown

    1

    Calculate post-money valuation

    Post-Money = Pre-Money + Investment

    The valuation that defines the new share price.

    2

    Compute investor equity

    % = Investment ÷ Post-Money

    The percentage of the company the new investor owns after closing.

    3

    Project founder ownership after

    Founder After = Founder Before × (1 − Investor %)

    Existing founder ownership is diluted proportionally to the new equity issued.

    Example Calculation

    pre Money:$2M
    investment:$500K
    founder Before:80%
    Result:Investor 20% · Founder after 64%

    Dilution benchmarks (June 2026)

    Typical per-round dilution by stage to help you calibrate your ask and term sheet.

    4 verified benchmarks·Sourced from SBA, NRA, Rock Health, Toast, CBRE, FDD filings & more
    Industry Low Average High Key drivers
    Pre-Seed
    8% 12% 15%
    Seed
    15% 20% 25%
    Series A
    20% 25% 30%
    Series B
    15% 20% 25%

    * Benchmarks reflect first 6–12 months to launch in USD. Figures vary by region, team size, and market conditions. Click any source to verify the underlying data.

    Expert tips for a 2026 raise

    Always negotiate post-money option pool

    A pre-money pool shuffle transfers dilution to founders only.

    💡 Action: Insist the option pool top-up sits inside the post-money capitalization.

    Model 3 rounds ahead

    Cumulative dilution from Seed → Series B routinely lands founders at 35–45%.

    💡 Action: Use the multi-round simulator before signing any single round.

    Refuse full-ratchet anti-dilution

    Broad-based weighted average is the 2026 standard.

    💡 Action: If the term sheet says full-ratchet, send back a redlined broad-based version.

    Plan a founder vesting refresh

    At Series A, ask for a 2-year refresh on founder shares.

    💡 Action: Include the refresh in the term sheet — easier than asking later.

    Secondary at Series B

    Take 5–10% off the table at Series B without spooking lead investors.

    💡 Action: Negotiate a structured secondary alongside the primary raise.

    Common equity mistakes to avoid

    Pre-money option pool shuffle

    Lead investor demands a fresh option pool included in pre-money.

    ✓ Instead: Move the pool top-up to post-money — recovers 3–5% founder ownership.

    Accepting 1× participating preferred

    Investors double-dip at exit (preference + pro rata share).

    ✓ Instead: Negotiate to 1× non-participating; cap participation at 2× if forced.

    Ignoring the liquidation stack

    Multiple preferred rounds can stack to wipe out founder proceeds.

    ✓ Instead: Run the exit waterfall at 3 exit valuations before signing.

    Raising too much too early

    38%+ dilution at Seed locks in a structurally bad cap table.

    ✓ Instead: Target 15–25% Seed dilution and use bridge SAFEs if needed.

    Real-world equity cap-table examples

    See how founders modeled dilution and negotiated better terms.

    Illustrative scenarios: composite examples built from typical figures, not verified results of named companies.

    AI Productivity SaaS

    B2B SaaS

    Challenge: Founders accepted a pre-money option pool shuffle without modeling the dilution impact.

    Pre-Money

    $8M

    Raise

    $2M

    Pool Shuffle

    +5%

    Hidden Dilution

    +4.2%

    Outcome: Renegotiated to a post-money option pool, recovering 4.2% founder ownership before closing.

    Marketplace Series A

    Consumer Tech

    Challenge: Term sheet included 1× participating preferred, materially reducing founder exit payout.

    Investment

    $8M

    Exit

    $120M

    With Participating

    $54M

    Non-Participating

    $66M

    Outcome: Negotiated to 1× non-participating preferred, saving $12M in founder proceeds at exit.

    Climate Hardware Startup

    CleanTech

    Challenge: Raised too much too early at a low valuation, locking in 38% Seed dilution.

    Seed Dilution

    38%

    Series A Dilution

    24%

    Founder After A

    29%

    Industry Norm

    45–55%

    Outcome: Used the equity calculator to right-size next round, raising less at a 3.2× step-up to preserve control.

    * Case studies are based on industry averages and anonymized data from similar companies.

    Validate your idea

    Numbers check out? Pressure-test the idea itself.

    Founders give up equity for validated traction. Build that proof before signing a term sheet.

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    Why Trust Our Calculators?

    Industry-Standard Formulas

    All calculations use formulas recognized by VCs, accelerators, and business schools worldwide.

    Built by Founders

    Created by entrepreneurs who've used these metrics to raise funding and scale their companies.

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    Live formula

    Inv ÷ (Pre + Inv) = %
    Founders64.0%·Investors20.0%·Post-Money$2.50M
    Standard
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