Enter the buys and sells for a position — a dividend stock you're tax-loss harvesting is the common case — and see exactly which losses IRC §1091 disallows, the adjusted cost basis on your replacement shares, and your net deductible loss after the $3,000 annual cap. Free, no signup, nothing leaves your browser.
| Ticker | Type | Date | Shares | Price/share | |
|---|---|---|---|---|---|
$ | |||||
$ | |||||
$ |
Net capital gain/loss
$0.00
Disallowed (wash sale)
$1,000.00
Offsets ordinary income
$0.00
Carries forward
$0.00
| Ticker | Date | Shares | Reported G/L | Disallowed | Wash sale? |
|---|---|---|---|---|---|
| XYZ | 2026-02-01 | 100 | $0.00 | $1,000.00 | ⚠️ Yes |
| Ticker | Loss sale | Replacement buy | Shares | Basis added |
|---|---|---|---|---|
| XYZ | 2026-02-01 | 2026-02-15 | 100 | $1,000.00 (+$10.00/share) |
Estimate only, computed from IRC §1091 mechanics over the trades you entered — not a substitute for your broker's 1099-B, which is the figure the IRS actually receives. Enter trades in chronological order for the most accurate result. Consult a tax professional before filing.
The default example: 100 shares bought at $50, sold at $40 (a $1,000 loss), then 100 replacement shares bought two weeks later at $42 — within the 61-day window, so the entire $1,000 loss is disallowed and added to the replacement lot's basis, making its true cost basis $52/share ($42 + $10 disallowed loss per share). If those replacement shares are later sold at $60, the taxable gain is $8/share ($800 total), not $18/share — the deferred loss reduced it, exactly as intended by the rule.
Sales are matched to purchase lots first-in-first-out (FIFO), and losses are matched to replacement purchases nearest in time first. Both are standard, defensible conventions when the IRS's own rules don't specify an exact matching order for a given set of trades — your broker's actual 1099-B is the figure that gets reported to the IRS and may use specific-lot identification instead of FIFO if you elected it.
Under IRC §1091, if you sell a stock or security at a loss and buy a substantially identical security within 30 days before or 30 days after the sale — a 61-day window total — the loss is disallowed for tax purposes. The disallowed amount is added to the cost basis of the replacement shares, so the loss is deferred rather than lost, and reduces your taxable gain (or increases your loss) whenever you eventually sell the replacement shares.
Calendar days, not trading days — weekends and holidays count. This calculator measures the window as the absolute difference in calendar days between the sale date and the purchase date, and flags any repurchase within 30 days in either direction (source: IRC §1091; IRS Publication 550).
The disallowance is proportional. If you sell 100 shares at a loss and buy back only 40 within the window, 40 shares' worth of the loss is disallowed and added to the basis of those 40 replacement shares; the loss on the other 60 shares is fully deductible as usual. This calculator computes that split automatically per lot.
Up to $3,000 per year ($1,500 if married filing separately) of net capital losses can offset ordinary income; any excess carries forward indefinitely to future tax years (source: IRS Topic 409, IRS Publication 550). This calculator applies that cap to your net result automatically.
Yes — the IRS treats a purchase in any account you control, including an IRA or your spouse's account, as a replacement purchase for wash-sale purposes. Worse, if the replacement shares are bought in an IRA, the disallowed loss cannot be added to that account's basis at all (IRA basis isn't tracked the same way), so the loss is permanently lost rather than deferred. This calculator assumes all trades are in the same taxable account; it does not model cross-account or IRA wash sales.
Yes. An automatic dividend reinvestment that buys more shares of the same stock counts as a purchase for wash-sale purposes just like a manual buy order. If you sell shares of a dividend stock at a loss while its DRIP is still reinvesting nearby dividends, that reinvestment purchase can trigger a wash sale — a common surprise for dividend investors tax-loss harvesting a position they still hold in a DRIP plan.
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This calculator performs arithmetic on the trades you enter and does not access your brokerage account or any market data. It is not tax advice; consult a tax professional and your broker's 1099-B before filing.