Wash Sale Calculator
Determine if your stock trade triggers the IRS Wash Sale Rule, which disallows deducting a loss if you buy a "substantially identical" security within 30 days.
Check Wash Sale
$
Date
you bought similar stock
Did you replace all sold shares?
How It Works
The Wash Sale Rule prevents you from claiming a loss on a security if you buy a "substantially identical" security within 30 days before or after the sale.
The 61-Day Window
The restricted period is 61 days total: the day of the sale, the 30 days before, and the 30 days after.
Consequences
- You cannot deduct the loss on your current tax return.
- The disallowed loss is added to the cost basis of the new replacement stock.
- This defers the tax benefit until you sell the replacement stock.
Use Cases
- Check whether repurchasing a stock after a loss sale falls within the 30-day wash sale window.
- Determine the adjusted cost basis for replacement shares after a wash sale is triggered.
- Plan the timing of tax-loss harvesting trades to avoid the wash sale rule.
- Verify whether switching between similar ETFs or mutual funds triggers a wash sale.
- Calculate the deferred loss amount that gets added to replacement share basis.
Assumptions & Limitations
- The wash sale window is 61 days total: 30 days before, the sale date, and 30 days after the sale.
- The rule applies to "substantially identical" securities; this tool does not determine substantial identity.
- Wash sales across different accounts (e.g., taxable and IRA) may still apply but are not modeled here.
- Partial replacement (buying fewer shares than sold) results in a proportional disallowance, which is simplified in this tool.
- The disallowed loss is added to the cost basis of the replacement shares, deferring (not eliminating) the tax benefit.
- This tool provides estimates for educational purposes only and does not constitute tax advice. Consult a qualified tax professional for your specific situation.
Sources & References
- IRC Section 1091 - Loss from Wash Sales of Stock or Securities
- IRS Publication 550 - Investment Income and Expenses (Wash Sales)
- IRS Schedule D Instructions - Capital Gains and Losses
- IRS Form 8949 Instructions - Sales and Dispositions of Capital Assets
- IRS Topic No. 409 - Capital Gains and Losses
Tax laws change frequently. Always verify current rates and thresholds on IRS.gov before making financial decisions.