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What the IRS wants in a gambling diary — and how to keep one that holds up

Publication 529, in its own words: what every entry needs, what backs it up, and why "at the time" is the point.

StampChip is a record-keeping tool. This page is information, not tax advice; what you can deduct depends on your return and your state. Checked against the sources below on 2026-10-28.

The four things every entry needs

If you deduct gambling losses, the IRS expects you to prove them, and the proof it names first is a diary. Publication 529 puts it plainly: "You must keep an accurate diary or similar record of your losses and winnings." It says the diary "should contain at least the following information":

  • "The date and type of your specific wager or wagering activity."
  • "The name and address or location of the gambling establishment."
  • "The names of other persons present with you at the gambling establishment."
  • "The amount(s) you won or lost."

That is the whole list: the date, the type of play, the place, who was with you, and the money. A diary with those four for every session is the baseline; a diary missing one of them is the first thing a reviewer will notice.

The records that back the diary up

The diary is the backbone, but Publication 529 also says: "In addition to your diary, you should also have other documentation." It lists what generally proves winnings and losses: "Form W-2G, Certain Gambling Winnings; Form 5754, Statement by Person(s) Receiving Gambling Winnings; wagering tickets; canceled checks; substitute checks; credit records; bank withdrawals; and statements of actual winnings or payment slips."

For specific kinds of play it names the detail that supports each one:

  • Slot machines: "A record of the machine number and all winnings by date and time the machine was played."
  • Table games: "The number of the table at which you were playing." "Casino credit card data indicating whether the credit was issued in the pit or at the cashier's cage."
  • Keno: "Copies of the keno tickets you purchased that were validated by the gambling establishment", "copies of your casino credit records, and copies of your casino check-cashing records."
  • Bingo: "A record of the number of games played, cost of tickets purchased, and amounts collected on winning tickets."
  • Racing: "A record of the races, amounts of wagers, amounts collected on winning tickets, and amounts lost on losing tickets."
  • Lotteries: "A record of ticket purchases, dates, winnings, and losses."

So for slots the machine number and the time you played it matter; for tables, the table number. Those are the details nobody remembers the next morning, which is why the record has to be made at the time.

Why "at the time" is the point

A diary written up in March from memory is not the same document as one kept session by session. The language is about a record of what happened, kept as it happened. The practical rules that follow:

  • One entry per session: when you sat down, where, what you played, what you brought in and what you left with.
  • Write down who was with you, even when it feels odd. It is one of the four required items.
  • Keep the paper the casino gives you (W-2Gs, payment slips, ATM receipts) with the entry it belongs to.
  • Keep the diary somewhere you will still have it in two years. A notes app that disappears with your next phone is not that.

What an entry looks like

One session, as a diary entry (fictional)

Sat Oct 24, 2026 · 7:48 PM – 9:52 PM · Spirit Mountain Casino, 27100 SW Salmon River Hwy, Grand Ronde, OR · Slots: Buffalo Gold, machine 2417 · With R. Alvarez · Money in $200 (cash), money out $340 · Won $140 · W-2G: none · Records: photo of the machine, player's card used · Check-ins stamped at 7:52 PM and 9:40 PM, both at the casino.

The same entry in the free log template is one row; in StampChip it is a session with two stamped check-ins.

The easy way: let the phone keep it

StampChip keeps exactly this diary: it asks for the date, the place, who was with you, what you played and the money, stamps each check-in with the time and place as it happens, and keeps everything on your own phone (nothing is sent to us). At tax time it builds a Preparer Pack: a PDF diary in Publication 529 order and a workbook with every session, for you or your preparer.

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Questions people ask

Does a casino win/loss statement replace the diary?

No. Publication 529 lists statements from the establishment among the documents that support your winnings and losses; the diary is a separate requirement.

Do I need the diary if I do not itemize?

Gambling losses are an itemized deduction, so the deduction only helps if you itemize; winnings are income either way. Whether you itemize is a question for your return, or your preparer.

What changed for 2026?

For tax years beginning after December 31, 2025, the deduction for wagering losses is limited to 90% of the losses (One Big Beautiful Bill Act, section 70114), and the W-2G reporting threshold for 2026 payments is $2,000. The details and where the repeal effort stands: Gambling losses on your 2026 return.

Sources