Cap Table Simulator
Multi-founder, multi-SAFE cap table simulator. Add up to 3 SAFE notes + a priced round. Y Combinator post-money methodology. Free.
Cap Table Simulator
Model a startup cap table through multiple SAFE notes plus a priced round. SAFEs convert at the lower of valuation cap or round price (with discount applied). Output: founder + option pool + SAFE + new investor percentages and post-money dollar values.
👥 Founders + employee pool (starting)
💰 Priced round
📝 SAFE notes (up to 3)
SAFE conversion breakdown
| SAFE | Invested | Converts at | Before the round | After the round |
|---|
Post-money valuation —; pre-money —, assumed to include the converting SAFEs (the YC default). Each SAFE converts at the lower of its cap and the pre-money valuation less its discount, then is diluted by the new money like every other holder.
How to Use the Cap Table Simulator
Enter today's ownership
Enter each founder's percentage and the option pool as they stand before any SAFE converts. If they add up to less than 100%, the rest is shown as other existing holders, who are diluted with everyone else rather than ignored.
Add SAFE notes
For each SAFE, enter the amount, the post-money valuation cap and any discount. Y Combinator's standard post-money SAFE comes in a cap version or a discount version; YC withdrew its cap-and-discount version in August 2021. A negotiated SAFE can carry both, so the tool accepts both and converts at whichever gives the investor the lower price.
Enter the priced round
Enter the new money and the post-money valuation of the priced round. Pre-money is post-money minus the new money, and, as in YC's default, it includes the SAFEs that convert in the round.
Read the post-round table
The tiles show each holder after the round, adding to 100%. The table shows every SAFE twice: its share just before the round (amount ÷ conversion valuation) and after it, once the new money has diluted it. The tool does not model a pool top-up or pro-rata rights; see the FAQ for how to approximate a top-up.
Cap Tables and SAFEs — The US Startup Operating Reality
What a post-money SAFE promises, and what it does not
Y Combinator introduced the SAFE, a simple agreement for future equity, in late 2013 as a replacement for convertible notes. It is not debt: there is no interest and no maturity date, just a right to shares when the company raises a priced round. In 2018 YC moved to the post-money SAFE, whose valuation cap is stated after all the SAFE money. That makes the SAFE's share easy to read, and YC's user guide gives the example: $500,000 on a $6.7 million post-money cap is about 7.5% of the company.
That 7.5% is the share just before the priced round. YC's guide is explicit that the cap is post the SAFE money but not post the new round's money, so "the safes will be diluted by the new money raised in the Equity Financing." A SAFE holding 15% before a round in which new investors take 25% ends with 15% × 75% = 11.25%. This calculator used to report the pre-round figure as the final one, which overstated what SAFE holders end with and understated the founders.
Cap or discount: which price wins
A cap converts the SAFE as if the company were worth the cap. A discount converts it at the round's share price less the discount, and because pre-money includes the converting SAFEs in YC's default, that works out as the SAFE's amount ÷ (pre-money × (1 − discount)). Where a SAFE carries both, it takes whichever price is lower. With this page's defaults, a $25 million post-money round raising $5 million has a $20 million pre-money. The first SAFE's 20% discount would price it at $16 million, so its $8 million cap wins, and $500,000 buys 6.25% before the round and 5.00% after it.
"A post-money cap fixes what a SAFE owns just before the priced round. The round's new money still dilutes it like everyone else."
What this model leaves out
Two things change real outcomes and are not modelled. A pool increase negotiated in the round: YC's guide says SAFEs are diluted by a pool created or enlarged as part of the round, but not by a pool that existed before it. And pro-rata side letters, which let SAFE holders buy part of the new round. Either can move the founders' final percentage by several points. Use this for scenario comparisons, such as a $20 million versus a $30 million post-money, and check the closing table your lawyers produce.
A SAFE's cap is fixed before the round, and the round still dilutes it
Y Combinator introduced the SAFE in late 2013 as a replacement for convertible notes, and moved to the post-money SAFE in 2018.
A post-money cap makes the SAFE's share amount ÷ cap: $500,000 on a $6.7 million cap is about 7.5%, per YC's guide.
That share is measured before the priced round. The new money dilutes it: 15% × (100% − 25%) = 11.25%.
A discount applies to the round's share price, which here is pre-money ÷ shares, not post-money.
YC removed its cap-and-discount post-money SAFE in August 2021; its standard versions are cap, discount or MFN.
SAFEs are diluted by a pool created or increased in the round, and not by a pool that existed before it (YC's guide).
The pre-money valuation includes the converting SAFEs unless the round's terms say otherwise.
A section 83(b) election must be filed within 30 days of the transfer of the restricted stock (IRS Form 15620).
Pro-rata side letters let SAFE holders buy into the round in which they convert, and are not modelled here.
At this page's defaults the SAFEs hold 8.75% before the round and 7.00% after it.
Frequently Asked Questions
- A simple agreement for future equity: an investor pays now and receives shares when the company raises a priced round (or cash on a sale or dissolution, in the order the SAFE sets out). Y Combinator introduced it in late 2013 to replace convertible notes, so it carries no interest and no maturity date. The post-money version, YC's standard since 2018, states its valuation cap after all the SAFE money, which makes the investor's share before the priced round simply amount ÷ cap.
- The original SAFE stated its cap on a pre-money basis, so every SAFE issued later diluted the earlier ones and nobody could say what they had sold until the round closed. The post-money SAFE states the cap after all the SAFE money: SAFEs no longer dilute each other, and each one's pre-round share is amount ÷ cap. Both are diluted by the priced round's new money, and the post-money version is also diluted by a pool increase made in that round.
- The highest valuation at which the SAFE converts. If the priced round values the company above the cap, the SAFE converts as if the company were worth the cap, so the investor gets more shares per dollar than the new investors pay for. If the round comes in below the cap, it converts at the round price, or at the discount price if it has one.
- There is no standard amount, and this page will not invent one. What the arithmetic shows is the cost: on a post-money cap, every $1 million at a $10 million cap is 10% of the company before the round. Add up all the SAFEs you plan to issue, divide each by its cap, and that is the share you are selling before the priced round dilutes everyone, them included.
- That depends on your investors and your plans, not on a rule of thumb. The arithmetic still matters: post-money SAFEs do not dilute each other, so their shares simply add up, and the total comes off the founders before the round. If that total is getting large, a priced round fixes a valuation for everyone at once. Run both plans here and compare the founders' final percentage.
- Not directly. When a priced round requires a bigger option pool, investors usually ask for it to be in the pre-money, so the increase dilutes existing holders rather than the new money, and YC's guide says post-money SAFEs are diluted by it too. To approximate it here, enter the founders and the pool as they would stand after the increase, with the founders' share reduced to make room, and treat the result as an estimate: the exact figure depends on whether the increase is counted before or after the SAFEs convert.
- A convertible note is debt: it accrues interest and has a maturity date, and in principle it must be repaid if it has not converted by then. A SAFE has neither. Y Combinator designed it to replace the convertible note for early fundraising. Both usually convert at a priced round, using a cap, a discount or both, so the conversion arithmetic in this tool applies to either, ignoring a note's accrued interest.
- There is no fair default, and this page does not suggest one. What matters for the cap table is that the split is agreed in writing early, and that founder shares usually vest, so a founder who leaves does not keep stock for work they never did. If founder stock is subject to vesting, a US founder who wants to be taxed on its value at grant rather than as it vests must file a section 83(b) election within 30 days of the transfer (IRS Form 15620).
- The arithmetic is the same anywhere: a cap or discount fixes a conversion price, and the priced round dilutes everyone. The legal instrument is not. The YC SAFE is written for US (Delaware) companies, and investors outside the US often use local equivalents with different terms. Have a lawyer in the company's jurisdiction confirm how your instrument converts before relying on any calculator, this one included.
- Two things this page can say with confidence. First, a US SAFE assumes a US company to issue shares from, so founders raising on YC SAFEs typically need a US parent company, which is a structuring decision for your lawyers and accountants. Second, if you hold restricted US stock and are taxable in the US, the 30-day 83(b) deadline applies to you. Everything else, including tax where you live, needs local advice.
Method & sources
How it computes
Post-money SAFEs converting in one priced round (YC Post-Money Safe User Guide, Feb 2023): pre-round share = amount / min(cap, pre-money x (1 - discount)), pre-money = post - new money and including the SAFEs; every holder, SAFEs included, then x (1 - new money / post). RecaBusiness.capTable, tested.
What this tool implements
- Bug fixed: the page reported each SAFE's pre-round share (amount / cap) as its FINAL share, so the priced round never diluted the SAFEs, and it took the discount off the POST-money valuation. At the defaults the SAFEs end at 7.00%, not 8.75%, and the founders at 32.85% and 25.55%. Founders and pool summing to under 100% are now reported as other holders instead of being scaled up into the founders.
- YC withdrew its cap-and-discount post-money SAFE in version 1.1 (28 Aug 2021); the page called a discount part of YC's standard SAFE. 83(b): Form 15620, due within 30 days of the transfer.
- Removed as unsourced: SAFE market share, Carta/AngelList user counts, Delaware share, typical splits, raise sizes and caps, CAFE/ASA naming and fundraising advice attributed to named firms. Pool increases and pro-rata rights are stated as not modelled.
Sources
- Y Combinator. Post-Money Safe User Guide, February 2023 (safe ownership = amount / post-money valuation cap; safes diluted by the equity financing's new money). https://bookface-static.ycombinator.com/assets/ycdc/Website%20Use…
- Internal Revenue Service. Form 15620, Section 83(b) Election (no later than 30 days after the date the property was transferred). https://www.irs.gov/pub/irs-pdf/f15620.pdf
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