Option pool sizing calculator.
Size the pool from the hires you plan before the next round: multiply each hire group by its typical grant and add them up, then subtract what is left in the current pool after the round. Two executives at 1%, six senior hires at 0.4% and twelve others at 0.1% need 5.6%; with 2% unallocated today, the top-up is 4%.
Top-up to add
4%
- Pool needed after the round
- 5.6%
- Existing pool after dilution
- 1.6%
- Effective pre-money
- $11,400,000
Indicative result from the numbers you enter. Not financial, tax or legal advice.
How it is calculated.
- Pool needed = executives x grant + senior hires x grant + other hires x grant.
- Investor stake = amount raised / (pre-money + amount raised).
- Existing pool after the round = unallocated pool today x (1 - investor stake).
- Top-up = pool needed - existing pool after the round, never below zero.
- Effective pre-money = headline pre-money - top-up x post-money, the value the existing holders actually get.
Worked example.
Twenty hires before the next round
| Step | Working |
|---|---|
| Pool needed | 2 x 1% + 6 x 0.4% + 12 x 0.1% = 2% + 2.4% + 1.2% = 5.6% |
| Investor stake | $3,000,000 / $15,000,000 = 20% |
| Existing pool after | 2% x (1 - 0.20) = 1.6% |
| Top-up | 5.6% - 1.6% = 4% |
| Effective pre-money | $12,000,000 - 4% x $15,000,000 = $11,400,000 |
Typical pool sizes.
Unallocated pools of roughly 10% to 20% of the post-money are often quoted for seed and Series A rounds, with the size falling as the company matures. The number that matters for you is the one your hiring plan needs until the next raise, usually 18 to 24 months of hires.
Where grant sizes come from.
The default grants are placeholders, not market data. Grant sizes depend on stage, role, location and cash salary, and they shrink as the company grows. Use your own bands, or the compensation data your investors or payroll provider can share, and keep them consistent with offers already made.
The effective pre-money.
A pool created before the round lowers the value existing holders receive, even though the headline pre-money stays the same. In the example the 4% top-up costs $600,000 of pre-money. A tight, plan-based pool is one of the clearest levers founders have in a term sheet.
Common mistakes.
- Accepting a round-number pool (10%, 15%) without a hiring plan to support it.
- Counting options already promised in offer letters as unallocated.
- Forgetting that refresh grants for current staff also come from the pool.
- Comparing headline pre-money across term sheets with different pool requirements.