Capital Gains and Loss Carryover Calculator (2026)
Net your short-term and long-term stock sales the way Schedule D does: the $3,000 loss deduction, the loss carried to next year (short-term or long-term), the tax on a net gain, the 3.8% tax and how much gain you can still take at 0%. From the Schedule D instructions and 26 U.S.C. 1211-1212.
Your 2026 sales
Use a minus sign for a loss. These are the totals from Form 8949 (or the totals on your Form 1099-B): proceeds minus basis, summed across all sales in each group. Add a loss disallowed as a wash sale back to your basis first (see the FAQ).
From line 8 and line 13 of last year's Capital Loss Carryover Worksheet (Schedule D instructions). Enter them as positive numbers. They stay short-term or long-term.
Everything else on your 2026 return
Only matters for the 3.8% tax, which starts at $200,000 of modified AGI ($250,000 joint). Wages and business income are not investment income.
Net capital loss on Schedule D
$11,000
$3,000 of it comes off your other income this year; $8,000 carries over to 2027.
What carries over to 2027
With no gains to offset it, $8,000 lasts 3 more years at $3,000 a year. Any gain you realise in a later year uses it up first, dollar for dollar. Short-term losses are used before long-term ones, and a carried-over loss keeps its character.
Estimate only, for federal income tax. It follows the 2025 Schedule D and its instructions (Capital Loss Carryover Worksheet), IRS Publication 550, 26 U.S.C. 1211(b), 1212(b) and 1411, and the 2026 amounts in Revenue Procedure 2025-32. Not financial or tax advice; check your own figures against your Form 1099-B and return or ask a tax professional.
Frequently asked questions
Q.How much of a stock loss can I deduct in one year?
Losses first cancel your capital gains of the year, short-term against short-term and long-term against long-term, then the two results cancel each other. If losses are still left, you deduct the smaller of the net loss and $3,000 ($1,500 if you are married filing separately) from your other income, and carry the rest to the next year (26 U.S.C. 1211(b); Schedule D, line 21). The $3,000 is not indexed.
Publication 550's example: a couple sells securities at a $7,000 loss, deducts $3,000 and carries $4,000 to the next year; with a $2,000 loss they deduct all of it. The calculator reproduces both (taxable income $26,000 after the deduction).
Q.Is the carried-over loss short-term or long-term?
It keeps the character it had. When the $3,000 is deducted, short-term losses are used first, even if you lost the long-term money first (Publication 550). Example: a $2,000 short-term loss and a $9,000 long-term loss total $11,000; the $3,000 deduction takes the $2,000 short-term loss and $1,000 of the long-term loss, so $8,000 carries over as a long-term loss and nothing as short-term.
It matters later: a long-term carryover reduces next year's long-term gains (taxed at up to 20%) before its short-term gains, and a short-term carryover is netted against short-term gains first, which are taxed at your ordinary rates. There is no expiry for an individual: the loss carries until it is used up, but the unused loss of someone who dies can be deducted only on their final return and does not pass to the estate (Publication 550).
Q.What if my income is too low to use the $3,000 deduction?
The carryover is figured after the deduction, using your taxable income, and the Capital Loss Carryover Worksheet only counts the deduction up to the taxable income it actually reduced (lines 1-4). A single filer with $6,000 of other income and a $7,000 short-term loss deducts $3,000 on the return but has no taxable income either way (the $16,100 standard deduction is bigger), so the whole $7,000 carries over instead of $4,000 (what carries over with $100,000 of other income). The statute (26 U.S.C. 1212(b)(2)) says the same thing through "adjusted taxable income". The calculator shows this case when it happens.
Q.Does the 3.8% investment income tax apply, and do losses reduce it?
The 3.8% tax is on the smaller of net investment income and the amount your modified AGI is over $200,000 ($250,000 joint). Net gain from sales cannot be below zero, carryovers reduce it, and when you have a net capital loss the $3,000 allowed reduces your other investment income (26 CFR 1.1411-4(d)(2), Example 1: a single filer with $300,000 of wages, $5,000 of interest and a $30,000 net loss has $2,000 of net investment income and carries $27,000 forward). The calculator takes the part of your other income that is investment income as an input because wages are not.
Q.What is a wash sale, and how do I enter one?
You cannot deduct a loss on stock or securities if, within 30 days before or after the sale, you buy substantially identical stock or securities, acquire them in a fully taxable trade, acquire a contract or option to buy them, or buy them in your IRA or Roth IRA. The spouse or a corporation you control buying also counts. The disallowed loss is added to the basis of the new shares (not when the purchase is in an IRA), which postpones the loss, and the holding period carries over (Publication 550, Wash Sales). This calculator does not detect them: enter your totals after the wash-sale adjustment, as your Form 8949 reports them.
Q.How much long-term gain can I realise at the 0% rate?
Long-term gains are stacked on top of your other taxable income and are taxed at 0% up to $49,450 of taxable income for a single filer ($98,900 joint, $66,200 head of household) in 2026 (Rev. Proc. 2025-32, section 3.03). Example: a single filer with $30,000 of taxable income before any gain and a $5,000 gain already has $14,450 of room; the next dollar is taxed at 15%. Deductions your income does not use count as room too, because they are taken first: with no other income the room is $65,550 for a single filer. The room figure leaves out state tax and anything else that moves with income (the Social Security tax torpedo, ACA premium credits, Medicare IRMAA, the 3.8% tax), so check those separately.
Q.Why might my tax software or an accountant get a different number?
Common reasons: wash-sale adjustments and basis reporting on your Form 1099-B; sales of collectibles, qualified small business stock or rental property (the 28% and 25% layers); investment interest (Form 4952); state tax; the alternative minimum tax; credits and deductions beyond the one you enter; and the Tax Table, which this calculator replaces with the exact bracket formula (a difference of a few dollars). Last year's carryover must come from last year's worksheet, which can differ from this one if last year's taxable income was low or negative.
Sources
- 2025 Instructions for Schedule D (Form 1040) — the Capital Loss Carryover Worksheet (lines 1-13) and the instructions for line 21
- 2025 Schedule D (Form 1040) — lines 1a-16 and 21: net short-term, net long-term, and the loss deducted on Form 1040 line 7a
- IRS Publication 550 (2025), chapter 4 — Capital Losses: the $3,000 limit, carryovers keep their character, short-term losses first, Worksheet 4-1, and Wash Sales
- 26 U.S. Code § 1211(b) — Limitation on capital losses (individuals: gains plus the lower of $3,000 and the excess loss)
- 26 U.S. Code § 1212(b) — Capital loss carrybacks and carryovers for individuals; § 1222 — the definitions of net short-term, net long-term and net capital gain
- 26 CFR § 1.1411-4(d) — Net gain for the 3.8% tax: not below zero, carryovers included, and the $3,000 allowed loss reduces net investment income (Examples 1 and 3)
- IRS Revenue Procedure 2025-32 — 2026 maximum zero rate and 15% rate amounts (section 3.03), tax brackets and the standard deduction