Section 83(b) Election Deadline & Stock Vesting 2026 Tax Calculator
An 83(b) election calculator estimates the tax you owe now at grant fair-market value versus the tax you would owe later at each vest, plus the strict 30-day filing window under IRC §83(b). Filed correctly, it converts ordinary income at vest into long-term capital gain at exit.
| Spread at grant (FMV − purchase) | — |
| Ordinary income at grant (with 83b) | — |
| Tax owed now (ordinary rate) | — |
| Ordinary income at vest (no 83b) | — |
| Tax at vest (no 83b) | — |
| Capital gain at exit (with 83b) | — |
| Total tax with 83b (grant + LTCG at exit) | — |
| Total tax without 83b (ordinary + LTCG on appreciation) | — |
| Filing deadline (30 days from grant) | — |
| Lifetime tax savings from 83(b) | — |
An 83(b) election calculator estimates the tax you owe now at grant fair-market value versus the tax you would owe later at each vest, plus the strict 30-day filing window under IRC §83(b). Filed correctly, it converts ordinary income at vest into long-term capital gain at exit, often saving founders, early employees, and consultants tens to hundreds of thousands of dollars on a successful exit.
How the 83(b) Election Works
Without an election, restricted stock or RSUs taxed under §83(a) generate ordinary income at each vesting event equal to FMV minus purchase price. If the stock appreciates, your ordinary income at vest grows with it. An 83(b) election opts to recognize the entire spread at grant instead — typically when FMV is low (pre-funding, pre-409A bump). Future appreciation then qualifies for long-term capital gains if you hold the shares more than a year from grant.
The 30-Day Filing Deadline (Hard Cutoff)
You must file the election with the IRS within 30 days of the grant date — no extensions, no exceptions. Mail (certified, return-receipt) is the safest method. As of mid-2024 the IRS allows e-filing via the Form 15620 process, but paper filing remains the default. Provide a copy to your employer and keep one with your tax records. Missing the 30-day window forfeits the election permanently — you cannot file late, even with reasonable cause.
When 83(b) Saves Money — and When It Doesn't
Save money: early-stage startup shares at $0.001 to $0.10 per share, low spread, high expected appreciation. The tax owed now is tiny; the savings at exit are huge. Lose money: publicly-traded RSUs where FMV is already material — paying ordinary income tax on $200K of phantom value with no liquidity to cover the bill, only to have the company crash and never vest. Run the calculator both ways. If grant FMV × shares × ordinary rate exceeds what you can comfortably write a check for, skip the election.
Common 83(b) Election Mistakes
(1) Missing the 30-day deadline — most common and unrecoverable error. (2) Filing for RSUs that aren't actually transferred at grant (RSUs are settled later — 83(b) doesn't apply). (3) Not paying the cash tax bill now and getting a 1099 surprise. (4) Forgetting to send a copy to the employer for payroll-tax withholding. (5) Filing for stock that ultimately doesn't vest — you don't get a refund of the tax paid at grant if shares are forfeited. (6) Skipping it for QSBS-eligible stock — 83(b) starts the 5-year QSBS clock immediately.
Last updated May 2026. Sources: IRC §83(b), IRS Form 15620 (2024 e-file), Treasury Reg §1.83-2.