Wash Sale Rule Calculator
Review the full 61-day window with loss, account, substantially-identical and matched-share gates. 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. Review note: Complete the account and substantially-identical review.
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
The calculation guide and this source trail show what the result means, where the rule came from and when it was last reviewed. This is source-and-calculation QA, not a claim of medical, legal, tax or other professional review; time-sensitive decisions still belong with the linked authority.
A visible path from input to answer.
Review the full 61-day window with loss, account, substantially-identical and matched-share gates. The page keeps the calculation scope and its limits beside the result so the output can be checked, copied or revisited.
- Read the record. The calculator uses Loss-sale trade date, Replacement acquisition date to check, Sale result, Replacement acquisition and Are the positions substantially identical? and 3 additional fields supplied in the form.
- Apply the scope. It applies the United States federal tax-lot review — IRS Publication 550 timing, account, quantity and substantially-identical gates reference and the explicit date, unit and counting conventions shown in the result.
- Expose the checkpoints. Intermediate rows, warnings and timeline events stay visible; the emphasized row identifies the primary checkpoint when one exists.
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. Review note: Complete the account and substantially-identical review.
- 61-day review windowJul 31, 2026 – Sep 29, 2026
- Candidate acquisition dateSep 9, 2026
- Record completenessIncomplete
Calculation purpose: Review the full 61-day window with loss, account, substantially-identical and matched-share gates. This is a high-sensitivity reference output; the linked authority or qualified professional controls the final decision.
Calendar inputs use plain year-month-day semantics. Leap days, month ends, date-pair order and unsupported dates are checked before the result is shown.
Rule set 2.0.0 · Last reviewed 2026-08-20 · Next review due 2027-02-20. The source panel below contains the linked evidence.
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.