Capital Gains Tax Calculator 2026
Calculates your federal capital gains tax for assets sold in 2026. Preferential LTCG rates (0%, 15%, 20%) and statutory 3.8% NIIT threshold calculation.
Capital Gains Tax Calculator 2026
Calculate federal taxes on short-term and long-term capital assets. Features 2026 statutory preferential thresholds (0%, 15%, 20%) and Net Investment Income Tax (NIIT 3.8%) surtax calculations.
Transaction Details & Income
NIIT Threshold ($200,000): Below NIIT Threshold
Effective Rate on Gain: 15.0% • Net Proceeds: $25,500
| Bracket Rate | Taxable Income Threshold |
|---|---|
| 0% Preferential | Up to $48,350 |
| 15% Standard | Up to $533,400 |
| 20% Maximum | Over $533,400 |
| +3.8% NIIT Surtax | AGI > $200,000 |
Worked Example — Long-Term Asset Sale ($30,000 Realized Gain)
Alex (Single Filer) reports $85,000 in ordinary taxable salary. He sells stock held for 4 years for $60,000 with a cost basis of $30,000, realizing a $30,000 long-term capital gain:
| Statutory Tier | Tax Base | Tax Liability |
|---|---|---|
| Combined Taxable Income | $85,000 salary + $30,000 gain = $115,000 | — |
| 0% LTCG Threshold (Single 2026) | Applicable up to $48,350 | $0.00 |
| 15% Preferential Capital Gains | $30,000 gain taxed at 15% ($48,350 to $533,400) | $4,500.00 |
| Net Investment Income Tax (NIIT) | Total $115,000 < $200,000 statutory threshold | $0.00 |
| Total Federal Tax on Sale | 15.0% effective tax rate | $4,500.00 |
| Net Cash Realized | $60,000 gross proceeds − $30,000 basis − $4,500 tax | $25,500.00 |
Tax Code Provisions (IRC §1(h) & §1411)
Capital gains on assets held for over one year qualify for statutory preferential tax rates under IRC §1(h). Brackets are indexed for inflation each tax year; for 2026, the 0% maximum threshold is $48,350 (Single) and $96,700 (Married Joint).
The Net Investment Income Tax (NIIT) was enacted under IRC §1411. It applies a 3.8% tax on the lesser of net investment income or the excess of modified AGI over statutory limits ($200,000 Single, $250,000 MFJ). Crucially, NIIT thresholds are not indexed for inflation.
Exclusions & Limitations
- State Taxes: Most states tax capital gains as ordinary income (e.g., California up to 13.3%, New York up to 10.9%), which are not reflected here.
- Depreciation Recapture: Real estate Section 1250 depreciation recapture taxed at up to 25% is excluded.
- Wash-Sale Restrictions: IRC §1091 wash-sale disallowance rules for repurchases within 30 days are not evaluated.
Calculation Methodology
Applies 2026 IRS preferential long-term capital gains statutory brackets (IRC §1(h)) and 3.8% Net Investment Income Tax thresholds (IRC §1411).
Calculates capital gains tax liability, statutory NIIT surtax, effective tax rate on the gain, and net post-tax cash proceeds.
Frequently Asked Questions (FAQ)
What qualifies as a long-term capital gain?
Assets held for longer than one full calendar year (366+ days) qualify for preferential long-term capital gains rates of 0%, 15%, or 20%.
What is the Net Investment Income Tax (NIIT)?
NIIT is a 3.8% statutory surtax under IRC §1411 on investment income for filers with MAGI exceeding $200,000 single or $250,000 married filing jointly.
How are short-term capital gains taxed?
Assets held for 12 months or less are classified as short-term and taxed at standard ordinary federal income tax rates between 10% and 37%.