How do I substantiate gambling losses for a client?
By the W2gMatch team · Sources checked 09-06-2026 · General information, not tax advice.
Substantiation is a contemporaneous diary plus third-party documents: the date and type of each wager, where it was placed, who was present, and the amount won or lost, supported by W-2Gs, win/loss statements, wagering histories and bank records. Operator statements alone are estimates. Under the 2026 90% limit, the substantiated loss figure also drives the phantom income calculation.
The standard
The IRS asks the taxpayer to keep an accurate diary or similar record of winnings and losses and to be able to provide receipts, tickets, statements or other records that show the amount of both. [1] The diary should show the date and type of each wager or wagering activity, the name and address or location of the establishment, the names of other persons present, and the amounts won or lost. [2] The publication then lists supporting documents by activity: validated keno tickets and casino credit records; machine numbers and dates for slot play; table numbers and casino credit card data; bingo games played and ticket costs; race records and losing tickets; lottery tickets and payment slips. [2]
Since the deduction is capped at winnings and, for tax years from 2026, at 90% of losses, [3] the same file that supports the losses also fixes the winnings figure the cap runs against.
A source hierarchy that holds up
- Forms the IRS already has. Every W-2G and 1099 under the client's SSN, from the Wage and Income transcript. These are the figures the return will be matched against.
- Operator wagering histories. The wager-by-wager export from each online book or app. Contemporaneous, third-party, and gross: the best evidence of both wins and losses.
- Operator win/loss statements. The annual win/loss statement (the operator's estimate of tracked wins and losses, usually disclaimed as not a tax document) from every operator, including the losing ones. Estimates, net, and limited to tracked play, but the document an examiner expects to see.
- Bank and card records. Deposits to and withdrawals from each operator, ATM withdrawals at casinos, and casino credit. They tie the operator documents to real money.
- The client's own log. The diary itself. Where it was kept as they went, it is the anchor; where it was reconstructed, it should say from what.
Where substantiation usually fails
- A book the client forgot. Losing accounts are the deduction. Ask for every operator, then check the bank records for deposits to ones not named.
- Netted statements used as gross. A statement showing a $12,000 net loss says nothing about winnings, which must be reported in full.
- Untracked cash play. Table play without a card, cash sports bets at a window, home games. Only the diary and any cash withdrawals support these.
- Calendar versus session. A statement is a calendar-year net. The session method needs per-session figures, which the statement does not give.
- W-2Gs double counted. A W-2G jackpot is inside the operator's statement, not in addition to it.
Casual and professional
For a client filing as a professional gambler on Schedule C, the amended statute folds otherwise allowable expenses of carrying on wagering into “losses from wagering transactions,” so they sit inside the same 90%-and-capped-at-gains limit. [3] The substantiation for the expenses is ordinary business substantiation; the substantiation for the wagers is the file above.
Presenting it
A workpaper that lists each operator, the documents received from it, the winnings and losses derived, and the reconciling items between the documents and the forms the IRS holds. Every figure on the return should trace to a line in that workpaper and from there to a document. That is what W2gMatch produces from the uploaded file; it is also what an examiner asks for first.
Related questions
Is a win/loss statement enough on its own?
No. The IRS standard is a diary supported by documents; the statement is one of the documents. A statement with no log and no wagering history invites the question of what it missed.
What if the client kept no log?
Reconstruct one from wagering histories, statements and bank records, and label it as reconstructed. It is weaker than a contemporaneous diary and far stronger than nothing.
What is a gambling client workpaper for tax purposes?
A gambling client workpaper is a comprehensive, organized compilation of a taxpayer's gambling winnings and losses, supported by contemporaneous records. Its purpose is to substantiate reported income and claimed deductions for gambling losses to the IRS, ensuring compliance and audit readiness. It reconciles W-2Gs, 1099s, win/loss statements, and personal logs into a single, traceable file.
What documents are essential for a gambling client workpaper?
Essential documents for a gambling client workpaper include IRS Forms W-2G and 1099, operator wagering histories, annual win/loss statements from all casinos and online platforms, bank and credit card records detailing deposits and withdrawals, and a detailed, contemporaneous personal gambling log. These records collectively substantiate both winnings and losses, as outlined in IRS Publication 529.
Can recreational gamblers deduct travel expenses related to gambling?
No, recreational gamblers cannot deduct travel, meals, or other expenses related to their gambling activities. For recreational gamblers, only actual wagering losses are deductible, and only as an itemized deduction on Schedule A, up to the amount of winnings. These non-wagering expenses are not considered deductible by the IRS.
Produce the workpaper from the documents
W2gMatch reads every W-2G, statement, history and transcript for a client, reconciles them, and writes the workpaper with a trail from each figure to its source document.
Sources
- IRS Tax Topic 419, Gambling income and losses, page last reviewed June 11, 2026
- IRS Publication 529, Miscellaneous Deductions, Gambling losses up to the amount of gambling winnings, Rev. December 2020
- 26 U.S.C. § 165(d), Wagering losses, as amended by Pub. L. 119-21 § 70114 (Legal Information Institute), amendment effective for taxable years beginning after December 31, 2025
Related
This page is general information about how U.S. federal and state tax rules apply to gambling, written to be checked against the sources it cites. It is not tax advice for your situation. A licensed CPA or enrolled agent should review your return before it is filed.