You can deduct $3,000 of net capital losses against ordinary income in 2026 ($1,500 married filing separately); everything above that carries forward indefinitely. The wash sale rule is a separate constraint — it does not cap how much you harvest, it disallows the loss on shares you replace with the same or a substantially identical security inside a 61-day window (30 days before the sale through 30 days after). Harvesting $20,000 of losses against $5,000 of gains erases the gains, deducts $3,000 this year, and carries $12,000 forward.
The 61-day window, $8,000 loss on 100 shares sold 2026-03-10
| Repurchase date | Days from the sale | Inside the window? | Loss you can claim |
|---|---|---|---|
| 2026-02-08 | -30 | Yes — wash sale | $0 |
| 2026-02-15 | -23 | Yes — wash sale | $0 |
| 2026-03-25 | +15 | Yes — wash sale | $0 |
| 2026-04-09 | +30 | Yes — wash sale | $0 |
| 2026-04-10 | +31 | No | $8,000 |
The window runs 30 days each side of the sale, so a repurchase 30 days after still washes the loss and one day later does not. A washed loss is not lost forever when the replacement sits in a taxable account — it is added to the new shares' basis and comes back when you sell them. Repurchasing inside an IRA disallows that portion permanently, with no basis adjustment.
Carrying the rest forward
| Tax year | Carryforward in | Deducted against ordinary income | Carryforward out |
|---|---|---|---|
| 2026 | $0 | $3,000 | $12,000 |
| 2027 | $12,000 | $3,000 | $9,000 |
| 2028 | $9,000 | $3,000 | $6,000 |
| 2029 | $6,000 | $3,000 | $3,000 |
| 2030 | $3,000 | $3,000 | $0 |
Losses net against gains of the same character first, then across characters; only what survives that netting hits the $3,000 annual limit, and the remainder carries forward with its character intact until it is used up. There is no expiry.
Methodology
The annual limit and the window length are CAP_LOSS_LIMIT and WASH_SALE_WINDOW_DAYS from QuantCalc's parity-tested capital-gains module; the netting and carryforward schedule come from netScheduleD() (IRC §1211(b) / §1212(b)) and each row of the window table from washSaleCheck() (IRC §1091). See the 2026 capital-gains bracket dataset.
Every figure on this page is computed at build time from QuantCalc's parity-tested calculation modules or a committed dataset — never hand-entered. Reference for research and planning only; not tax, legal, or investment advice.
Model this for your own numbers
The free QuantCalc calculator applies the same brackets to your actual income and gains.
Open the free calculator →Harvesting gains and losses across a portfolio? See the Tax Tools suite.
Changelog
- v2026.1 — first publication. Figures computed from the 2026 tax-constants mirror and committed datasets.
Cite this dataset
QuantCalc Research (2026). How much can I deduct in capital losses in 2026, and what triggers the wash sale rule?. https://quantcalc.app/answers/capital-loss-deduction-and-wash-sale-rule/ (accessed <date>).
BibTeX
@misc{quantcalc2026howmuchcanideductincapitallossesin2026an,
title = {How much can I deduct in capital losses in 2026, and what triggers the wash sale rule?},
author = {{QuantCalc Research}},
year = {2026},
url = {https://quantcalc.app/answers/capital-loss-deduction-and-wash-sale-rule/},
note = {Accessed <date>}
}Machine-readable citation metadata (schema.org identifier and citation fields) is embedded in this page's JSON-LD, at the stable identifier https://quantcalc.app/answers/capital-loss-deduction-and-wash-sale-rule/.