Free calculator · Venture & Startup Finance
Founder Dilution Across Rounds
Compounds founder ownership downward across successive financing events, multiplying retained ownership by one minus each round’s dilution. Inputs are the dilution percentages for the option pool, seed SAFEs, Series A, and Series B.
By Devon Coombs, CPA, MBA · Teaching Professor of Finance, Santa Clara University · Reviewed August 2026
From the author: Devon Coombs, CPA, MBA teaches finance at Santa Clara University and works with corporate teams on practical AI.
AI training for finance teams · Consulting · The 10 Laws of Finance
Interactive Tool
Founder Dilution Across Rounds
Founder ownership after all rounds
36%
started at 100%
Dilution compounds: each round's percentage is taken on a base that already includes every prior round, so a string of ordinary rounds carries founders from 100% to a minority stake faster than the individual numbers suggest.
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This calculator comes from the free Entrepreneurial Finance course, where the concept is taught with readings, worked examples, and practice questions.
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Built by Devon Coombs, CPA, MBA, Teaching Professor of Finance at Santa Clara University.