Enter your trade dates to see whether a loss sale falls inside the 61-day wash sale window
Estimates only, not financial advice. What you type stays on your device. Checked against sources on 29 Sept 2026.The wash sale rule disallows a loss when you buy the same or a substantially identical security within 30 days before or after the sale. Selling 100 shares at a $1,000 loss on January 15, 2026 and buying 60 back on February 5, 2026 defers $600 into the new shares' basis; $400 stays deductible. Enter your own trades.
Rates and rules read from IRS Publication 550, Investment Income and Expenses (Wash Sales) on 29 Sept 2026; they may have changed since.
Enter the "Date you sold them" for the loss sale, with the shares sold, cost basis and proceeds.
Enter the date of every purchase of the same or a substantially identical security, in any account.
Read the "Wash sale window" to see which purchases fall within 30 days before or after the sale.
Check "First safe day to buy back" and "Loss you can deduct now".
A wash sale happens when you sell a stock or fund at a loss and buy the same or a substantially identical security within 30 days before or after the sale. The IRS then refuses the loss for now. It is not gone: IRS Publication 550 moves the disallowed loss into the cost basis of the replacement shares, and the holding period of the shares you sold carries over to them.
The window counts calendar days. Day 30 after the sale is still inside; day 31 is the first safe day to buy back. Purchases in the 30 days before a sale count too, which is the part people forget when they add to a losing position and then sell the older shares.
What this calculator does not do: decide whether two funds are substantially identical, handle options, short sales or a spouse's account, or read your Form 1099-B. Your broker reports wash sales only within one account and the same CUSIP; the rule applies across all of them. An estimate, not tax advice.
The rest of the article, and all 6 questions about Wash Sale Calculator, are on the Wash Sale Calculator page.
The wash sale rule stops you deducting a loss on a stock or security if you buy the same or a substantially identical one within 30 days before or after the sale. The loss is not lost: IRS Publication 550 adds it to the cost basis of the new shares, so it lowers the gain or raises the loss when you finally sell them.
Wait until the 31st day after the sale. The window runs from 30 days before the sale to 30 days after it, 61 days in all, and a purchase on day 30 still counts. Buying in the 30 days before the sale also counts, so check recent purchases before you sell.
Add the disallowed loss to what you paid for the replacement shares. In the IRS example, 100 shares bought for $1,000 and sold for $750 give a $250 loss; buying 100 again for $800 makes the new basis $1,050. The holding period of the old shares is added to the new ones as well.
Yes. Publication 550 lists buying substantially identical stock for your IRA or Roth IRA as a wash sale. Unlike a purchase in a taxable account, the disallowed loss is not added to any basis, because IRA assets have no basis for this purpose. The loss is gone permanently, which makes this the costliest version of the rule.
Rates and rules change; check the source before you rely on a figure.
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