2026 educational tax estimate
2026 Stock Capital Gains Tax Calculator
Estimate short- or long-term federal tax, NIIT, state tax, after-tax gain, and net sale proceeds.
Calculation methodology reviewed by Carina Luo, CPA
Based on 2026 federal tax rules. Last reviewed July 2026.
Direct answer
A stock sale creates capital gain or loss equal to proceeds minus adjusted basis. Short-term gains are taxed through ordinary-income brackets; long-term gains stack on top of taxable income and move through the 0%, 15%, and 20% bands. High-income taxpayers may also owe 3.8% NIIT.
Your inputs
Quick estimate
Used to approximate capital-gain stacking and NIIT.
2026
Estimated sale impact
Estimated total tax
$9,835
Includes federal capital-gain tax, NIIT, and the entered state rate.
Capital gain / loss
$35,000
Federal tax
$5,250
NIIT
$1,330
State tax
$3,255
After-tax gain
$25,165
Net sale proceeds
$50,165
Effective tax rate on gain
28.1%
Educational estimate only, not tax advice. Final results depend on full income, deductions, residency, prior returns, and transaction records.
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How the estimate works
The calculator subtracts adjusted basis from proceeds. Short-term federal tax is the incremental ordinary tax under 2026 brackets. Long-term tax uses the 2026 0%/15%/20% thresholds after accounting for other taxable income. NIIT is estimated from the statutory MAGI threshold.
Important limitations
- Enter adjusted basis, not necessarily the number printed on a 1099-B for RSU, ESPP, or exercised options.
- This tool does not net other gains and losses, wash sales, carryovers, QSBS exclusions, or multi-state sourcing.
Frequently asked questions
When is a gain long term?
Generally, the asset must be held for more than one year. Equity-compensation holding periods may start at vest, exercise, or purchase depending on the award.
Does the calculator include NIIT?
Yes, as a simplified estimate using the entered income as an approximation of MAGI before the sale.
Can a capital loss erase prior W-2 equity income?
Not directly. Net capital loss generally offsets capital gains first, with a limited annual deduction against ordinary income.