Post-money SAFE calculator

See what your post-money SAFEs own at their caps, then convert them into a priced round, with discounts and the option-pool top-up modelled the way the YC SAFE actually reads.

SAFE holders own after the round—

Round price per share: —
Post-money valuation: —
Existing holders own: —
New investors own: —

How each SAFE converts
SAFE	Price	Priced by	Shares	Owns

Cap table after the round
Holder	Shares	Owns

For planning and negotiation prep, not legal, tax or investment advice. Real documents differ in the details — check the numbers with your counsel against the actual term sheet. Everything runs in your browser; nothing you type is sent anywhere.

How a post-money SAFE converts

A SAFE (simple agreement for future equity) is a right to shares later, usually at the next priced round. The version most US startups now sign is Y Combinator’s post-money SAFE, whose defining feature is that the valuation cap is a post-money number: a $1 million SAFE with a $10 million cap buys 10% of the company as it stands just before the priced round, counting all the SAFEs. That is why the “at the cap” view above simply adds up amount ÷ cap for each SAFE.

When the priced round happens, each SAFE converts at the lowest of up to three prices:

Cap price = post-money cap ÷ Company Capitalization (all shares, options, the existing unissued pool and every converting SAFE).
Discount price = the round’s price per share × (1 − discount), if the SAFE has a discount.
Round price = what the new investors pay, for an uncapped SAFE with no discount.

The SAFE’s shares are its amount divided by that price.

Why the pool top-up dilutes SAFE holders

Priced-round investors usually want the unissued option pool enlarged before they come in, so the new options don’t dilute them. The YC post-money SAFE excludes that increase from Company Capitalization, so the top-up dilutes SAFE holders alongside the founders. Set the pool target to 0% to see how much of your SAFE holders’ ownership the shuffle costs them. The calculator solves the round price, the SAFE conversions and the pool increase together, because each one depends on the others.

A worked example

A company has 9,000,000 fully diluted shares, including a 1,000,000-share unissued pool, and one $1 million SAFE with a $10 million post-money cap. It raises $5 million at a $20 million pre-money with no pool top-up. The SAFE owns 10% of Company Capitalization, so it converts into 1,000,000 shares and Company Capitalization becomes 10,000,000. The cap price is $1.00 and the round price is $2.00, so the cap wins. The new investors buy 2,500,000 shares. After the round the SAFE holder owns 8% (10%, diluted by the 20% sold in the round), and existing holders own 64% plus the 8% pool.

What this calculator doesn’t model

Pre-money SAFEs (the pre-2018 YC form) measure the cap before the SAFE money, so SAFEs dilute each other; MFN-only SAFEs take the best terms of later SAFEs; and some rounds negotiate a different pool treatment. Read your documents. For the trade-offs between instruments, see SAFE vs. convertible note, or convert a note with the convertible note calculator.