Wash Sale Checker
Check a list of trades for possible wash sales — losses on sales where the same security was bought within 30 days before or after.
For information and education only — not financial advice. Results are estimates based on the numbers you enter; check important decisions with a qualified professional.
How to use
- 1Enter each trade on its own line: date, buy or sell, shares, price (e.g. 2025-03-01 sell 10 45).
- 2Loss sales with a purchase within 30 days are flagged.
How it's calculated
A loss sale is flagged if a purchase of the same security happened from 30 days before to 30 days after the sale date. Losses use the average cost of shares held before the sale.
Frequently asked questions
What is the wash sale rule?
US tax rules disallow a loss if you buy the same or a 'substantially identical' security within 30 days before or after selling it at a loss. The loss is added to the new shares' cost basis.
Does it apply across accounts?
Yes — including IRAs and a spouse's accounts. This checker only sees the trades you enter.
Is this tax advice?
No. Brokers report wash sales within one account on Form 1099-B; use this for planning and confirm with a tax professional.