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SAFE conversion simulator.

Model how a post-money SAFE converts at your next priced round. Enter the SAFE terms and the round, and see exactly how shares, prices, and ownership shake out across founders, the SAFE holder, and new investors.

  • Side-by-side cap-based vs. discount-based conversion price
  • Founder, SAFE, investor, and option-pool ownership after the round
  • Updates live as you type — no email required to use it
  • Optional emailed PDF report if you want to save the scenario
Open the simulator
Inputs & results

Edit any field. Results update instantly. Uses the standard post-money SAFE conversion mechanic from Y Combinator’s 2018 template.

Company & SAFE
Total fully-diluted shares outstanding before the SAFE.
$
$
%
Priced round
$
$
%
New investors typically require the top-up to come out of the pre-money cap (founder dilution).
Conversion math
Round price per share
—
Cap-based SAFE price
—
Discount-based SAFE price
—
SAFE converts at (lower of two)
—
Stakeholder Shares % post-round
Founders & existing holders — —
SAFE holder — —
New round investors — —
Option pool (top-up) — —
Post-round fully diluted — 100.0%
Founders SAFE New investors Option pool
Optional · Save this scenario
Email me a PDF report of this scenario.

We’ll send a clean one-pager with the inputs you used, the conversion math, and the post-round cap table — useful for sharing with co-founders or counsel.

We’ll send the PDF and occasional corporate-records tips. Unsubscribe any time. We don’t share your email.

How the math works

Post-money SAFE conversion in four steps.

This simulator uses the post-money SAFE conversion method — the dominant form since YC’s 2018 update. The math is mechanical but easy to get wrong on a napkin.

1
Round price per share

Take the pre-money valuation and divide by the pre-money fully-diluted share count, including the new option pool top-up. That sets the price new investors pay.

2
Cap-based SAFE price

Divide the SAFE’s post-money cap by the post-money capitalization (founders + pool + SAFE shares, excluding new money). This is the price the SAFE pays if the cap binds.

3
Discount-based SAFE price

Multiply the round price by (1 − discount). This is the price the SAFE pays if the discount is the better deal.

4
SAFE converts at the lower price

SAFE holders get whichever price gives them more shares — the lower of the cap-based and discount-based prices. New investors’ shares are then issued at the full round price.

After the round

A SAFE conversion is the moment your cap table either holds or breaks.

If your share register, board resolutions, and certificate sequence aren’t reconciled before the round closes, the conversion produces inconsistencies that surface during diligence. Octelligence keeps your cap table, register, and certificates synced so closings don’t stall.

See Cap Tables & Financing
FAQ

Common questions

Post-money. The YC SAFE was updated in 2018 to lock the SAFE holder’s ownership at the cap regardless of how much other SAFE money comes in. Pre-money SAFEs still exist but are rare in new deals; if you’re modelling one, treat the cap as pre-money and the result will be approximate.

Most SAFEs carry both a valuation cap and a discount, and the holder converts at whichever produces more shares. If the round prices below the cap, the discount kicks in. If the round prices above the cap, the cap binds. The simulator shows both so you can see which is doing the work.

This version models one SAFE. For two or more SAFEs at once, use the multi-SAFE batch conversion simulator — it reconciles the whole stack in one pass, since each SAFE’s converted shares feed back into every other SAFE’s price.

By convention, the pool top-up comes out of the pre-money cap, diluting existing holders before the new money lands. The simulator follows that convention. If your term sheet places the pool top-up post-money, the round price will be higher and the SAFE will likely convert at the cap.

Yes — the calculator is sharable by URL once you’ve entered numbers (your inputs encode into the link). Or request the emailed PDF report above to keep a clean record alongside your cap-table model.
Related concepts

The glossary behind the math.

Definitions of every term the simulator uses, plus the related cap-table and corporate-records pieces.

SAFE (post-money)
The conversion form this simulator models
Valuation cap
The ceiling on the conversion price
Discount rate
The alternative pricing path at conversion
Cap table
Where the converted shares land
MFN clause
How earlier SAFEs match later terms
Pro-rata rights
SAFE-holder rights in the next round
Multi-SAFE Batch Simulator
Same math, for a stack of SAFEs at once
Cap Table Dilution Calculator
Model the full priced round after conversion
Corporate Records Health Check
See if your records will hold up at closing
When the spreadsheet model isn’t enough.

Octelligence runs your cap table, share register, and certificates from a single source of truth — so SAFE conversions and priced rounds reconcile automatically.

Sign up See Cap Tables

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Add the SAFE Conversion Simulator to your own page. The widget links back to Octelligence.