Is my trade a wash sale under IRS rules?

Use this wash sale rule checker to screen whether selling an investment at a loss and buying the same or substantially identical security near the sale date may disallow the loss. It focuses on the 30-day window before and after the loss sale.

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wash sale rule checker

Quick answer

A wash sale can occur when you sell at a loss and buy the same or substantially identical security within 30 days before or after the sale. The loss is usually disallowed and added to basis.

Also answers

  • wash sale calculator
  • 30 day wash sale rule
  • disallowed loss calculator
  • stock loss wash sale

Good fit when

  • Checking loss trades before tax-loss harvesting
  • Reviewing repurchase timing
  • Avoiding disallowed capital losses

Have ready

  • Loss sale date and amount
  • Replacement purchase dates
  • Security and account details

Result you get

Wash-sale risk flag, affected window, and disallowed-loss note.

How this calculation works

  • Checks for repurchases within 30 days before or after a loss sale.
  • Flags potential disallowed losses under wash sale rules.
  • Estimates how the loss may adjust cost basis.

Common mistakes and caveats

  • Substantially identical securities can trigger wash sale rules.
  • This tool is a screening estimate; confirm with tax records.

FAQ

Does a wash sale eliminate the loss forever?

No. The disallowed loss is generally added to the basis of the replacement shares.

Last updated & sources

Last updated June 4, 2026.

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