Wash Sale Rule Calculator
without the guesswork.
Wash Sale 30 Day Window Calculator — Review the full 61-day window with loss, account, substantially-identical and matched-share gates. Uses a focused calculator with visible assumptions. Inputs stay in your browser.
The federal wash-sale window runs from 30 days before through 30 days after a loss sale—61 calendar days including the sale date. Timing alone is not enough; the loss, account relationship and substantially-identical test all matter.
Context matters.
- Use trade dates for market securities and review purchases before and after the loss sale across all relevant accounts, including a spouse's transactions and IRA or Roth IRA acquisitions.
- Substantially identical is a facts-and-circumstances tax test. Options, contracts, preferred/common stock relationships and replacement securities can require professional analysis.
- A disallowed loss is generally added to replacement-property basis, but an IRA or Roth IRA replacement has a special adverse basis result. Match tax lots and quantities with a qualified tax professional.
Sources & scope
This page shows the source trail, jurisdiction and review date alongside the result. Always confirm time-sensitive rules with the linked authority.
What to know before using the result.
Why is the wash-sale window 61 days?
It includes the 30 calendar days before the loss sale, the sale date and the 30 calendar days after it. Both boundary dates are part of the review window.
Which accounts and transactions must be reviewed?
Review relevant taxable accounts, IRA and Roth IRA purchases, a spouse's activity, controlled entities and contracts or options to acquire. Timing and matched quantities can create a partial wash sale.
What does substantially identical mean?
It is a facts-and-circumstances federal tax test, not simply a matching ticker check. If the relationship is uncertain, CalcSpan blocks a clean conclusion and calls for tax-lot review.