Learn: the wash-sale rule across all your accounts
Every guide we've written, grouped so you can go from "what is a wash sale?" to "how do I report the one my broker missed?" Primary sources throughout — IRS Publication 550, IRC §1091, Rev. Rul. 2008-5. The methodology page documents how the checker works.
Start here
The rule, the window, and why no broker sees your accounts at other brokers.
The wash-sale rule, explained for active traders
What IRC §1091 actually says: the 61-day window, replacement-share matching, basis adjustment, options and DRIPs, and how deferrals snowball onto a 1099-B.
The cross-account trap brokers don’t track
The IRS applies the rule across every broker, your IRAs and your spouse’s accounts; each broker sees only its own. How the gap bites, and how to check yours.
The 61-day window, with the exact dates
30 days before, the sale day, 30 days after. Both boundary days count, trade date governs, and day 31 is the first clean re-buy date.
Wash sale examples you can check yourself
Seven made-up cases (basic, partial, another broker, an IRA, a call option, a January re-buy, and a file that starts too late) with a CSV for each to re-run in the free checker.
The rules
The cases that cost the most and the definitions the statute never pinned down.
IRA wash sales: why the loss is gone forever
A re-buy in your traditional or Roth IRA within the window doesn’t defer the loss — Rev. Rul. 2008-5 disallows it permanently, and your broker isn’t required to warn you.
“Substantially identical”: where the line actually is
What’s clearly identical (same ticker, options on it), what’s ordinarily not (different companies — except in reorganizations), and the ETF-pair gray zone (SPY vs VOO).
“Wash sale loss disallowed” on your 1099-B, decoded
Why the number can be huge, whether the money is gone (usually not — except IRAs), the sold-everything case, and what your broker’s figure leaves out.
Reporting & forms
What the broker reports, what you must add, and where it goes.
1099-B box 1g: what your broker’s number covers
Brokers only have to report wash sales for identical securities inside one account. What’s included, what it may leave out, and how to reconcile it.
1099-B doesn’t match your wash sales? What to check
Why a broker’s box 1g can differ from your records: one account, identical securities, IRAs, spouses, options. A troubleshooting list.
Form 8949 code W: the wash-sale adjustment
Code W in column (f), the disallowed amount in column (g) — when your broker enters it for you, and when (cross-account cases) you must.
TurboTax with wash sales across multiple accounts
TurboTax won’t combine your brokers’ 1099-Bs to catch cross-account washes. Where the adjustment goes and how to enter it, step by step.
Tools & templates
Free, no signup: the seasonal checklist, the spreadsheet, and the honest comparison.
Year-end wash-sale checklist (tax year 2026)
The dates that matter, what to check before and after each harvest sale, and the January reconciliation — as a page and a printable one-page PDF.
Tax-loss harvesting deadline 2026: the dates that matter
Dec 31 is the last trading day, Nov 30 is the last loss sale you can re-buy within 2026, and a late-December loss stays washable by re-buys into January 2027.
Free wash-sale spreadsheet template (Excel)
Prebuilt 61-day window formulas, first-clean-re-buy dates and open-window alerts — plus the honest limits of tracking wash sales by hand.
Wash-sale tracking software, compared (2026)
Every way to track wash sales — paid software, broker 1099-Bs, scripts, spreadsheets and our free checker — on cross-account coverage, account linking and IRA detection.
Add the checker to your phone’s home screen
The same website, opened from an icon on iPhone or Android. Nothing is uploaded; your data stays in that phone’s browser.
Canada
For Canadian taxes. Our checker is for US taxes today.
Broker export walkthroughs
Where the CSV export lives at each broker, the format quirks we parse, and what that broker's own wash-sale flag does and doesn't cover.
Done reading? Check your own accounts.
Drop CSV exports from every broker and IRA — violations, open danger windows and a year-end summary, computed in your browser. Free, no signup, nothing uploaded.