SAFE Calculator
See what a post-money SAFE converts into at your next priced round, and how stacked SAFEs add up before you sign.
What each SAFE converts into
| SAFE | Converts at | Price that applies | Ownership |
|---|---|---|---|
| SAFE 1 | $5,000,000 | Cap | 10.0% |
Total SAFE dilution
10.0%
Founders after SAFEs
90.0%
Founders after next round
Add next round
For post-money SAFEs: ownership = SAFE amount ÷ valuation cap. With a discount and a next round entered, the SAFE converts at whichever gives the investor the better price: the cap or the discounted pre-money. Founders after the next round are diluted by the new money on top of the SAFEs. Ignores the option pool.
Educational estimate, not legal or financial advice.
How it works
Model your SAFE in 3 steps
Enter the SAFE amount and the post-money valuation cap.
Add a discount if your SAFE has one, and your expected next round if you know it.
Add more SAFEs to see your total dilution across all of them.
Worked example
A $500K SAFE at a $5M cap
Inputs
- SAFE amount
- $500,000
- Post-money cap
- $5,000,000
- Discount
- 20%
- Next round pre-money
- $8,000,000
- Next round raise
- $2,000,000
Result
- Price that applies
- Cap
- Investor owns
- 10%
- Founders after next round
- 72%
The cap beats the discount, so the investor owns 10% before the seed round.
How we got there
A post-money SAFE's ownership is just the SAFE amount divided by the cap: $500,000 / $5,000,000 = 10%, before any priced round.
The 20% discount would price the SAFE at $6,400,000 ($8,000,000 x 0.8). The $5,000,000 cap gives the lower price per share, so the cap wins and the SAFE converts at 10%.
Founders hold 90% after the SAFEs convert. The new seed investors then take $2,000,000 / $10,000,000 post-money = 20%, which leaves founders at 90% x 80% = 72%.
Reading your result
When your SAFE math is healthy, and when it isn’t
Good sign
All your SAFEs together stay under about 20% of the company before the priced round.
Red flag
Stacked SAFEs past 25%, or a cap you cannot grow into by the next round.
A post-money SAFE fixes the investor's ownership the moment you sign. Every new SAFE you sign adds to your dilution, and the earlier SAFE holders are not diluted by later SAFEs. That is why stacking several SAFEs quietly costs founders more than they expect.
The ownership shown is before your priced round. When you raise that round, the new investors dilute everyone, including the SAFE holders. Keep a running total of every SAFE you sign, and update your cap table the same day.
FAQ
SAFE questions founders ask
A SAFE (Simple Agreement for Future Equity) lets an investor give you money now in exchange for shares later. In a post-money SAFE, the cap includes the SAFE money itself, so the investor's ownership is simply the amount divided by the cap.
The investor gets whichever gives them the lower price per share. The calculator compares both and shows which one wins.
Not on paper, because no shares are issued yet. In practice the ownership is already committed, so treat it as dilution from the day you sign.
There is no fixed number, but once SAFEs add up to more than 20% to 25% of the company, the priced round becomes harder and founders often feel the squeeze.
The calculator follows the standard post-money SAFE structure that Y Combinator published. Always check the exact terms in the document you sign.