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SAFE conversion

SAFE calculator: exact post-money & pre-money conversion

Enter a SAFE’s investment, valuation cap and discount, then the priced round it converts at — Foundily shows the shares issued, the resulting ownership, the conversion price, and exactly which term (cap or discount) bound the deal.

Live SAFE calculator
Edit any field — recomputes instantly

The priced round it converts at

SAFE ownership
7.50%
fully diluted, after the round
Conversion price
$0.9000
Valuation cap applied
Shares issued
1,111,111
Effective valuation
$13.3M
what your SAFE 'bought' at
StakeholderTypeInvestedSharesOwnership
Existing shareholdersCommon—10,000,00067.50%
Option PoolOptions—00.00%
Your SAFESAFE$1M1,111,1117.50%
Priced roundPreferred$5M3,703,70425.00%
Total (fully diluted)14,814,815100%

How it works

1. Post-money SAFEs fix ownership first

A post-money SAFE's ownership is investment ÷ post-money valuation cap, measured before the new round's money arrives. That fraction is fixed the moment the SAFE is signed — the priced round only dilutes it.

2. The discount is a separate floor

If the SAFE also carries a discount, Foundily prices it at both the cap and the discount off the round price, then uses whichever gives the investor more shares — the term that actually binds.

3. Pre-money SAFEs use a circular solve

Pre-money (legacy) SAFEs price against the pre-round fully-diluted share count, which itself depends on how many shares other SAFEs take — Foundily resolves this with an exact fixed-point solver, not an approximation.

4. One engine, every surface

This calculator, the dilution and cap-table tools, and the public API all call the same conversion function — so the number your lawyer sees and the number your agent gets back always match.

Frequently asked

What's the difference between a post-money and pre-money SAFE?+

A post-money SAFE (the YC 2018+ standard) fixes the investor's ownership percentage directly: investment ÷ post-money cap. A pre-money (legacy) SAFE instead fixes a price per share based on the pre-round fully-diluted share count, so its final ownership depends on how many other SAFEs and options are outstanding.

Which wins — the valuation cap or the discount?+

Whichever gives the SAFE holder more shares. Foundily prices the SAFE at the cap and at the discount off the round's price per share, then takes the better of the two — the one that actually binds — and shows you which term won.

Does the SAFE's ownership change once the option pool is topped up?+

Yes, if the SAFE is pre-money and the pool basis includes it. Post-money SAFE ownership is fixed at signing and is only diluted by the incoming round; a pool top-up created in the same round dilutes it exactly the same way it dilutes founders.

Can I model more than one SAFE at once?+

This page is built for a single SAFE against one priced round. To stack multiple SAFEs, an option pool and a round together, use the cap table calculator, or model a full multi-round scenario with the dilution calculator.

Need this in your own tool or agent?

The exact same engine is available as a JSON API — one key, deterministic results, an OpenAPI spec and an MCP server.

Use this from the API →