1. Your trades
A CSV or pasted spreadsheet range with a header row. Columns: date, symbol, action (buy/sell), quantity, price (or amount), and optionally account (anything containing IRA, Roth or 401 is treated as retirement) and cost basis for sells. Without a basis column, sales use first-in, first-out lots from the same list, so include the original purchases.
Choose a file or paste the list, then click Check for wash sales.
Result
| Sale | Symbol | Gain / loss | Disallowed | Claimable loss | Replacement purchases | Buy back safely from |
|---|
How it works, and what it leaves out
- Window: 30 days before through 30 days after the sale date, inclusive: 61 days.
- Matching: purchases of the same ticker, in any account in your list. Each replacement share is used against one sale only. Shares are matched in date order.
- Partial wash: if you bought back fewer shares than you sold, the disallowed part of the loss is proportional to the shares replaced.
- Basis: disallowed loss is added to the basis of the replacement shares in taxable accounts, and carries into later sales in the same list. Holding period carries over; the page does not track it.
- Rules reviewed: 2026-10-06, by the author from IRC section 1091, IRS Publication 550 and Revenue Ruling 2008-5, not by a tax professional. Rules can change.
- Not decided: whether two different securities are substantially identical (a different ETF tracking the same index, options, bonds), a spouse's or entity's accounts, dividend reinvestments you did not list, short sales, crypto treatment, commodities and Section 1256 contracts, and the tax rate your loss is worth.
Common questions
What is the wash sale rule?
If you sell a security at a loss and buy substantially identical shares within 30 days before or after the sale (a 61-day window), the loss is disallowed for now. It is added to the basis of the replacement shares, and the holding period carries over, so the loss comes back when you finally sell those shares without another wash.
Does a wash sale count across accounts?
Yes. The rule looks at you, not at one brokerage account. A purchase in a second taxable account, a spouse's account or an IRA can wash a loss, and brokers' 1099-B forms generally report wash sales only within the one account they hold. This page checks every account in the list you give it.
What if the replacement shares were bought in an IRA?
The loss is disallowed and, under IRS Revenue Ruling 2008-5, the basis is not added back anywhere: the loss is permanently gone. The page flags these separately because they cost the most.
How do I report a wash sale?
On Form 8949, enter code W in column (f) and the disallowed amount in column (g) as a positive adjustment. The report CSV from this page has that figure for each sale. Check the instructions for the form and confirm with a tax professional.
When can I buy the stock back without a wash sale?
The 31st day after the sale, provided you also made no purchase of the same security in the 30 days before it. The page prints that date for each loss sale.
Is my trade list uploaded anywhere?
No. It is read in your browser and nothing is sent; a test in the code asserts there are no network calls.