Practical guide
Post-money SAFE ownership before and after a new round
Follow a simple SAFE ownership scenario through a later share issue and identify the terms the two-input model omits.
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Does a modeled SAFE percentage stay fixed forever?
No. A percentage estimated from investment and a post-money cap does not mean later financing can never dilute the holder. Keep the initial SAFE scenario separate from the subsequent share issue and the rights attached to the actual instrument.
A two-stage illustration
Assume the simplified cap-based calculation gives 5% from a $500,000 investment at a $10 million post-money cap. Then assume, solely for illustration, that conversion has occurred and a later issue gives new investors 20% of the resulting company, with no other changes.
An existing 5% holding becomes 5% × 80% = 4%. The one-percentage-point decrease is 20% of the prior 5% holding. The arithmetic illustrates later dilution; it does not determine the conversion mechanics of a specific SAFE.
Use this tool for the first stage. The equity dilution calculator can illustrate the second stage if you have consistent before-and-after share counts. Do not enter a new cap into the SAFE calculator and assume it models a priced round.
Keep participation separate
If an investor has and exercises a right to buy additional shares, the holder’s share count changes too. Y Combinator describes pro rata rights in an optional side letter. Whether such a right exists in your case, and how it operates, must come from the signed documents.
For a reviewable scenario, list the initial investment, cap, assumed conversion basis, new share issue, and any additional investment separately. Combining them into one unexplained percentage hides the assumptions most likely to change the result.
Follow-on financing questions
Can two SAFEs simply be added together?
Only after checking their respective terms and capitalization treatment. The tool models one investment and one cap. Different caps, discounts, and document versions need a more complete analysis.
Does this calculate my exit proceeds?
No. It does not model preferences, debt, taxes, transaction costs, or sale proceeds. A percentage ownership scenario is only one input to that separate calculation.
Use the safe calculator to reproduce the scenario with your own inputs.