Free tool
Founder vesting calculator
See exactly how much equity has vested at any point in a schedule — and what a cofounder would keep if they left.
After 18 months
Vesting monthly; fully vested at month 48.
| Month | Vested equity | Of grant |
|---|---|---|
| 12 (cliff) | 6.25% | 25% |
| 24 | 12.50% | 50% |
| 36 | 18.75% | 75% |
| 48 | 25.00% | 100% |
How vesting is calculated
Before the cliff, nothing has vested. At the cliff, the months already served vest at once (12 of 48 months = 25% on a standard schedule). After that, an equal slice vests every month until the period ends. Real agreements can differ — quarterly vesting, acceleration on a sale, or credit for time already worked — so check your own documents.
What is a standard founder vesting schedule?
Four years with a one-year cliff is the most common: nothing vests for the first 12 months, 25% vests at the cliff, and the rest vests monthly over the following 36 months.
What happens to unvested shares if a cofounder leaves?
Under a typical founder stock agreement the company can buy back unvested shares, usually at the original (very low) price, so the departing founder keeps only what has vested.
Can vesting start before we incorporate?
Yes — founders often agree a vesting start date that credits time already worked. Agree it explicitly in your founder agreement and have a lawyer document it.
Read more: What is a vesting cliff? · Vesting acceleration · Equity split calculator
General information, not legal or tax advice.