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Free Capital Gains Tax Calculator
Compute federal capital gains tax on any sale: short-term gains (≤365 days) taxed as ordinary income via bracket walk, long-term gains (≥366 days) taxed at preferential 0/15/20% rates under IRC § 1(h). LTCG stacks on top of ordinary income for bracket placement. NIIT 3.8% applied automatically when AGI exceeds $200k single / $250k MFJ. "Hold to long-term" scenario shows exact tax savings from waiting until day 366.
Use 2026 for current-year planning; switch to 2025 for a sale you report on the return you file in early 2026.
The sale
More than 365 days = long-term (preferential rate). 365 or fewer = short-term (ordinary rate).
Your tax context
LTCG stacks above this — your bracket depends on the total.
NIIT 3.8% applies above $200k single / $250k MFJ (IRC § 1411).
Tax owed
$4,500
Effective rate: 15.0% of the $30,000 gain.
Holding period
long-term
Tax owed
$4,500
long-term · effective 15.0%
Tax
$4,500
Net
$45,500
📐 Open methodology, sources & limitations
Formula
Gain or loss = sale proceeds − cost basis Holding period = long-term if days held > 365, else short-term Short-term: gain taxed as ordinary income. tax = bracket walk(other income + gain) − bracket walk(other income) Long-term (IRC §1(h)): preferential 0% / 15% / 20% rates. LTCG stacks ON TOP of ordinary income for bracket placement, filling the 0/15/20% bands per the selected-year LTCG thresholds. NIIT (IRC §1411) = max(0, min(gain, AGI − NIIT threshold)) × 3.8% applies only when AGI exceeds the threshold. Total tax owed = capital gains tax + NIIT Net proceeds = sale proceeds − total tax owed Long-term scenario savings = short-term tax − long-term tax (when short-term)
Assumptions
- Long-term treatment requires more than 365 days held; 365 days or fewer is short-term.
- LTCG breakpoints follow the selected tax year. 2025 (Rev. Proc. 2024-40): single 0% to $48,350 / 15% to $533,400 / 20% above; MFJ 0% to $96,700 / 15% to $600,050. 2026 (Rev. Proc. 2025-32): single 0% to $49,450 / 15% to $545,500; MFJ 0% to $98,900 / 15% to $613,700.
- Long-term capital gain stacks above the ordinary income you enter for bracket placement.
- Net Investment Income Tax of 3.8% applies on the lesser of the gain or AGI over $200,000 (single) / $250,000 (MFJ).
- Cost basis is taken as entered; you should include commissions and fees in it yourself.
Sources
- IRC §1(h) — Maximum capital gains rate (0/15/20%) — §1(h)
- IRC §1411 — Net Investment Income Tax (3.8%) — §1411
- IRC §1091 — Loss from wash sales of stock or securities — §1091
- IRS Rev. Proc. 2024-40 — 2025 inflation-adjusted LTCG thresholds — §3.03
- IRS Rev. Proc. 2025-32 — 2026 inflation-adjusted LTCG thresholds — §3.03
- IRS Topic No. 409 — Capital Gains and Losses
This tool does NOT model:
- Collectibles 28% maximum rate (IRC §1(h)(4))
- Section 1250 unrecaptured depreciation taxed at 25%
- Qualified small business stock exclusion (IRC §1202)
- Wash-sale loss disallowance (IRC §1091)
- State and local capital gains taxes
- Alternative Minimum Tax interaction
Last reviewed: 2026-06-12 · Tax year modeled: 2025 & 2026 (selectable)
This methodology section exists so you can verify the math. We show our formulas because you deserve to know how a number was calculated. This is calculation transparency, not financial advice.
What changed for 2026
The long-term capital gains rates are still 0%, 15%, and 20% for 2026 — only the income breakpoints between them moved, per the IRS inflation adjustments in Rev. Proc. 2025-32. The 0% band widens slightly, so a retiree or low-income year can absorb a bit more gain tax-free in 2026. The 3.8% Net Investment Income Tax thresholds ($200,000 single / $250,000 MFJ) are set by statute and never adjust for inflation, so each year more filers cross them. The more-than-one-year holding-period rule is unchanged. Pick the year you plan to sell in the calculator above.
| Figure | 2025 | 2026 |
|---|---|---|
| 0% LTCG bracket top — single | $48,350 | $49,450 |
| 0% LTCG bracket top — married filing jointly | $96,700 | $98,900 |
| 15% LTCG bracket top — single | $533,400 | $545,500 |
| 15% LTCG bracket top — married filing jointly | $600,050 | $613,700 |
| NIIT threshold — single / MFJ (statutory) | $200,000 / $250,000 | $200,000 / $250,000 |
Short-term vs long-term — the holding period that changes everything
The single biggest lever in capital-gains tax is whether you held the asset for more than one year(long-term) or one year or less (short-term). Short-term gains are taxed as ordinary income — same as wages — at your marginal bracket of 10–37%; to see where a gain lands inside your whole return, run the federal income tax calculator. Long-term gains get preferential rates of 0%, 15%, or 20% under IRC § 1(h). For a high earner in the 32% bracket, holding 1 day longer to convert short-term to long-term can save 17 percentage points of tax. On a $50,000 gain, that's $8,500 just for waiting a day.
2025 LTCG brackets
Per IRS Rev. Proc. 2024-40 § 3.03:
- Single: 0% up to $48,350; 15% from $48,350 to $533,400; 20% above
- MFJ: 0% up to $96,700; 15% to $600,050; 20% above
- HoH: 0% up to $64,750; 15% to $566,700; 20% above
LTCG stacks ON TOP of ordinary income for bracket placement. If you have $50k of wages and $30k of LTCG as a single filer, the wages fill brackets up to $50k, then the $30k LTCG starts at $50k. Since $50k is already above the $48,350 zero-bracket cap, the LTCG is in the 15% bracket — total tax on the LTCG = $30k × 15% = $4,500.
Net Investment Income Tax (3.8%)
Per IRC § 1411, single filers with AGI above $200,000 (or $250,000 MFJ) pay an additional 3.8% Net Investment Income Tax on the lesser of (a) net investment income or (b) AGI over the threshold. So a single filer with $230k AGI and a $30k LTCG pays NIIT on min($30k, $230k − $200k) = $30k × 3.8% = $1,140 — on top of the 15% federal LTCG. Effective rate becomes 18.8%, not just 15%. Also note that a large gain with no withholding behind it can require quarterly estimated tax payments to avoid an underpayment penalty.
Common capital-gains mistakes
- Selling on day 365. The IRS counts FROM the day after acquisition — so a stock bought Jan 1 must be sold Jan 2 of the following year or later to qualify as long-term. One day off, and the entire gain is short-term.
- Forgetting the wash-sale rule. If you sell at a loss and buy back the same security (or a substantially identical one) within 30 days before or after, the loss is disallowed under IRC § 1091. Common trap with tax-loss harvesting.
- Not adding commissions to basis. Brokerage commissions, fees, and reinvested dividends add to your cost basis. Forgetting them inflates your reported gain and overpays tax.
- Ignoring step-up at death. Inherited assets get a basis step-up to FMV at date of death (IRC § 1014). If you sell shortly after, gain is computed from that stepped-up basis — often near-zero. A massively underused planning tool for highly-appreciated assets held by the elderly.
- Forgetting state tax. Federal LTCG rates are nice, but most states tax capital gains as ordinary income (CA, NY, NJ, MA, etc. all do). The 15% federal rate becomes ~22% effective once you add state.
- Wash-sale on crypto. Wash-sale rules technically don't apply to crypto under current IRS guidance (IRS treats crypto as property, not securities). But this is actively being legislated; check current status.
Frequently Asked Questions
What's the difference between short-term and long-term capital gains?+
Short-term gains (held 365 days or fewer) are taxed at your ordinary income rate (10/12/22/24/32/35/37%). Long-term gains (held more than 365 days) are taxed at preferential rates of 0/15/20% under IRC § 1(h). For high earners, the gap can be 22+ percentage points — a major reason to hold investments at least 366 days.
When does the holding period start?+
The day AFTER you acquire the asset. So a stock bought on January 1 must be sold on January 2 of the following year or later to be long-term. The IRS published this rule in Rev. Rul. 66-7 and it's been law for decades. One day off and the gain is short-term.
What are the 2025 and 2026 LTCG brackets?+
For 2025 (Rev. Proc. 2024-40): Single: 0% to $48,350, 15% to $533,400, 20% above. MFJ: 0% to $96,700, 15% to $600,050, 20% above. HoH: 0% to $64,750, 15% to $566,700, 20% above. For 2026 (Rev. Proc. 2025-32): Single: 0% to $49,450, 15% to $545,500; MFJ: 0% to $98,900, 15% to $613,700; HoH: 0% to $66,200, 15% to $579,600. Use the year toggle in the calculator to switch. MFS uses single thresholds at 0% and 15% but 20% kicks in lower.
How does LTCG bracket stacking work?+
Your ordinary income fills the LTCG brackets from the bottom up. With $50k ordinary income and $30k LTCG as a single filer, the $50k consumes the 0% bracket (which ends at $48,350); the $30k LTCG falls entirely in the 15% bracket = $4,500 tax. If your ordinary income were $20k instead, $28,350 of the LTCG would be in 0% and $1,650 in 15%.
What is NIIT?+
Net Investment Income Tax — an additional 3.8% surtax on investment income for high-AGI filers (IRC § 1411). Applies to single filers above $200k AGI / $250k MFJ. Tax base = lesser of (a) net investment income or (b) AGI over threshold. Effective LTCG rate becomes 18.8% for many high earners (15% federal + 3.8% NIIT), not just 15%.
How do capital losses work?+
Capital losses offset capital gains dollar-for-dollar. If losses exceed gains in a year, up to $3,000 of net loss can offset ordinary income (single or MFJ); the rest carries forward indefinitely under IRC § 1212(b). Strategic tax-loss harvesting at year-end is a major planning tool.
What's the wash-sale rule?+
If you sell at a loss and buy back the same security (or a "substantially identical" one) within 30 days before or after the sale, the loss is disallowed under IRC § 1091. The disallowed loss adds to the basis of the replacement security. Wash-sale traps tax-loss harvesters frequently. Note: under current IRS guidance, wash-sale rules do NOT apply to crypto (treated as property, not securities), though this is actively being legislated.
Is my data stored?+
No. All math runs in your browser. Your sale details and income never leave your device.
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