Free calculator
SAFE & startup equity calculator pre-money vs post-money SAFEs
Model your SAFEs, the option pool and a priced round, and see the price per share, what each SAFE converts into and who owns what afterwards. The math follows Y Combinator’s SAFE documents.
Cap table today
All issued common stock.
Outstanding plus promised.
Reserved, not yet granted.
SAFEs, in the order you signed them
Priced round
Includes the converting SAFEs and the pool top-up, as most term sheets do.
Share of fully diluted shares after the round.
Runs in your browser. Nothing you type is sent or stored.
Price per share in the round
$1.1145
Post-money valuation $20M. Founders go from 92.5% to 51.54% fully diluted.
- Founders after
- 51.54%
- Founder dilution
- 44.28%
- Pool top-up (shares)
- 1,694,571
- New investor shares
- 4,486,425
- Post-money valuation
- $20,000,000
- Fully diluted shares after
- 17,945,701
How each SAFE converts
| SAFE | Converts at | Price | Shares | After |
|---|---|---|---|---|
| SAFE 1 | Its cap | $0.3400 | 588,235 | 3.28% |
| SAFE 2 | Its cap | $0.6800 | 1,176,470 | 6.56% |
Ownership before and after the round
| Holder | Before | After | Shares after |
|---|---|---|---|
| Founders | 92.5% | 51.54% | 9,250,000 |
| Options granted | 6.5% | 3.62% | 650,000 |
| Unissued pool | 1% | 10% | 1,794,571 |
| SAFE 1 | — | 3.28% | 588,235 |
| SAFE 2 | — | 6.56% | 1,176,470 |
| New investors | — | 25% | 4,486,425 |
| Total | 100% | 100% | 17,945,701 |
Fully diluted percentages. “Before” is today, with the SAFEs not yet converted. Prices are not rounded and shares are rounded down (the pool top-up up), so a real closing can differ by a few shares. Not legal or financial advice.
Quick answer
How does a post-money SAFE convert?
A post-money SAFE buys amount ÷ post-money cap of the company before the priced round: $1M on a $10M cap is 10%. Its price is the cap ÷ the company capitalization (all shares, options, the existing pool and every SAFE). It then converts at that price, or at the round price if that gives more shares, and is diluted by the new money and the new pool.
How to use the SAFE calculator
- Enter today’s cap table
Founders’ shares, options granted or promised, and the unissued option pool.
- Add your SAFEs in order
For each: amount, valuation cap, discount, post-money or pre-money cap, and whether it has an MFN clause.
- Describe the priced round
Pre-money valuation, new money and the unissued pool the investors want after the round.
- Read and export
See the price per share, each SAFE’s shares and the ownership table, then download it as CSV or copy the link.
How the calculator works
Post-money SAFE (YC’s current form): Safe Price = Post-Money Valuation Cap ÷ Company Capitalization. Company Capitalization counts, just before the round, every issued share, granted and promised option, the existing unissued pool and the shares every SAFE converts into, but not the new money or the pool increase made for the round. So each SAFE at its cap owns amount ÷ cap of that total, and SAFE holders do not dilute each other.
Pre-money SAFE (the original form, retired by YC in 2018): Safe Price = Valuation Cap ÷ (issued shares + options + unissued pool + the pool increase for the round), with every SAFE left out, as in Example 2 of YC’s user guide. Discount: the round price × (100% − discount). Each SAFE converts at whichever of the round price, its cap price and its discount price gives it the most shares.
The priced round: price per share = pre-money valuation ÷ pre-money fully diluted shares, where those shares include the converted SAFEs and the pool top-up that brings the unissued pool to its target share after the round. That is the usual term sheet, and the convention in YC’s examples. Because the price, the SAFE shares and the top-up depend on each other, the calculator solves them together exactly. An MFN SAFE takes the terms of a later SAFE in the list when they give it more shares.
Post-money SAFE: price = cap ÷ company capitalization; shares = amount ÷ price
Pre-money SAFE: price = cap ÷ (shares + options + pool + pool top-up)
Discount price = round price × (1 − discount)
Round price = pre-money valuation ÷ (shares + options + pool + top-up + SAFE shares)
Pool after = target × fully diluted shares after the roundWorked example (YC’s user guide, Example 1)
- Today: 9,250,000 founder shares + 650,000 options + 100,000 unissued pool = 10,000,000 shares.
- SAFEs: $200,000 on a $4M post-money cap (5%) and $800,000 on $8M (10%): 15% in all.
- Company capitalization = 10,000,000 ÷ (1 − 15%) = 11,764,706; the SAFEs get 588,235 and 1,176,470 shares.
- Series A: $5M at $15M pre with a 10% pool after: pool top-up 1,694,571 shares, price $15M ÷ 13,459,276 = $1.1145.
- New investors get 4,486,425 shares (25%); founders go from 92.5% to 51.5% fully diluted.
Pre-money vs post-money: what changes
A pre-money valuation is the company’s value just before the new money; post-money adds the money raised: $2M at $8M pre is $10M post, so the investor owns 20%. On a SAFE the difference is who absorbs the dilution. With a post-money cap, each SAFE’s ownership is fixed when you sign, and every new SAFE dilutes the founders only. With a pre-money cap, later SAFEs dilute earlier ones too, and nobody knows the exact percentage until the round.
Why the option pool matters so much
Investors usually ask for an unissued pool of around 10% after the round and count it in the pre-money valuation. The new shares for that pool come out of the existing holders, not the new investors: it lowers the price per share. Post-money SAFE holders are diluted by that top-up too, because it is new hiring capacity paid for by the round, as YC’s user guide explains.
Discounts and MFN clauses
A discount converts the SAFE at a percentage below the round price; with a cap as well, the investor takes whichever gives more shares. An MFN SAFE has no cap or discount of its own: if you later sign a SAFE with better terms, the holder can switch to those terms, once, taking the whole later instrument rather than picking clauses.
SAFE and dilution questions
- What is the difference between pre-money and post-money?
- Pre-money is the valuation before new money comes in; post-money is pre-money plus the money raised. $2M at an $8M pre-money valuation is a $10M post-money valuation, and the investor owns $2M ÷ $10M = 20%.
- How much of my company does a SAFE give away?
- For a post-money SAFE, the amount ÷ the post-money cap, before the priced round: $500,000 on a $5M cap is 10%. The round then dilutes that stake, and a round priced below the cap gives the SAFE more.
- Is a post-money SAFE better for founders?
- It is easier to understand: you know exactly what each SAFE sells. But because SAFE holders do not dilute each other, every extra SAFE comes entirely out of the founders. A pre-money SAFE spreads that dilution, at the cost of uncertainty.
- What is a valuation cap on a SAFE?
- The highest valuation at which the SAFE converts. If the priced round values the company above the cap, the SAFE converts at the cap’s lower price per share and gets more shares than the new investors per dollar.
- Do SAFE holders get diluted by the option pool?
- Post-money SAFE holders are not diluted by the pool that exists before the round, but they are diluted by the pool increase made as part of the round, alongside the founders.
- What does MFN mean on a SAFE?
- Most favoured nation. The SAFE has no cap or discount, but if the company later issues SAFEs on better terms, the holder can amend theirs to match the later SAFE in full, usually once.
- How is the price per share calculated in a priced round?
- Pre-money valuation ÷ pre-money fully diluted shares. Those shares usually include the converted SAFEs and the option pool top-up, which is why both lower the price.
- How do I make a cap table?
- List every holder with their shares: founders, granted options, the unissued pool, converted SAFEs and new investors. Divide each by the fully diluted total. This calculator builds it for you and exports it as CSV.
Cite this tool
Free to link and quote. Use this reference:
SaaSCity, "SAFE & Startup Equity Calculator", October 27, 2026. https://saascity.io/free-tools/safe-calculator