How we calculate

What we collect

For each scratch-off game on sale, the lottery publishes its game number, name, ticket price and a prize table. Each row of the table (a tier) gives a prize amount, the odds of winning it, how many were printed and, in most states, how many are still unclaimed. Some lotteries also publish how many tickets were printed and the overall odds of winning any prize.

We collect those facts, usually once a day, and nothing else. When a lottery does not publish a number, we show "Not published" and never fill in a guess.

Return per $1

Return per $1, which statisticians call expected value (EV), is what a ticket pays back on average for each dollar spent. We show it in cents. A figure of 76.5¢ means that, averaged over every ticket left, each dollar spent comes back as 76.5 cents in prizes. The other 23.5 cents is the lottery's share. It does not mean any one ticket returns 76.5 cents: almost every ticket returns nothing or a small prize, and a few return a lot.

We work it out at two moments.

At launch

Every prize is still in play.Return at launch = (sum of prize amount x prizes printed, for each tier) / tickets printed / ticket price

Now

Only prizes still unclaimed count, spread over the tickets we estimate are still unsold.Return now = (sum of prize amount x prizes left, for each tier) / estimated tickets left / ticket price

Return now can rise above the launch figure when big prizes stay unclaimed while small ones are cashed, and it falls when top prizes are claimed early. The change since launch is printed next to every figure: a rise in ink with a plus sign, a fall in red with a minus sign.

Tickets printed and tickets left

Lotteries publish prizes left, not tickets left, so we estimate it in three steps.

1. Tickets printed. We use the lottery's published figure when there is one. Otherwise we estimate it as the overall odds times the total number of prizes, when every tier's total is published. Failing that, we use the tier with the most prizes and published odds: odds times prizes printed.
2. Share of prizes left. Prizes left divided by prizes printed, counting only tiers where the lottery publishes both numbers.
3. Tickets left. Tickets printed times the share of prizes left. We label this number "estimated" wherever it appears.

A worked example

A $10 game with 1,000,000 tickets printed and this prize table:

• $100,000: 4 printed, 2 left
• $1,000: 1,000 printed, 450 left
• $100: 20,000 printed, 8,000 left
• $20: 100,000 printed, 41,000 left
• $10: 200,000 printed, 79,000 left

At launch the prizes add up to $7,400,000 across 1,000,000 tickets: $7.40 per $10 ticket, or 74.0¢ per $1.

Now 128,452 of 321,004 prizes are left, a 40% share, so about 400,157 tickets are left. The prizes still unclaimed add up to $3,060,000, or $7.65 per remaining $10 ticket: 76.5¢ per $1, up 2.5¢ since launch. On the game page that reads: "On average a $10 ticket returns $7.65. That is $2.35 less than it costs."

Top prizes

The top prize is the tier with the highest cash amount. "Top prizes left" counts the prizes left in that tier (in every tier with that amount, if there are several). A game whose top prizes are all claimed, or that the lottery has ended, drops out of every ranking and is listed separately under "No top prizes left".

Assumptions and limits

• Prizes are claimed in proportion to tickets sold. This is the standard approximation behind any tickets-left estimate. It overstates tickets left for a game where winners are holding prizes they have not claimed yet.
• Published counts trail real claims. Lotteries update their tables on their own schedule, and prizes are claimed between our updates. When a game shows 100¢ or more per $1, we say so plainly and treat it as a ceiling, not a promise.
• Non-cash prizes are left out. A car or a trip has no stated cash value, so it is not added to the return. This understates the return for games that offer them.
• Tiers missing counts are left out. When a lottery does not publish how many prizes of a tier were printed or are left, that tier cannot be counted, and we say "Not published" in the prize table.
• Taxes and shared prizes are ignored. Figures use prize amounts as the lottery states them, before tax.
• Rounding. We store return per $1 to four decimal places and show it in cents to one decimal. The dollar sentence on each game page rounds to whole cents and always adds up to the ticket price.

Every game is designed to pay back less than it costs on average. A higher number means you lose less, not that you will win.

Freshness

Each state shows when its prize data last updated successfully.

• Under 24 hours: shown as live.
• 24 to 48 hours: the update stamp turns amber.
• Over 48 hours: a notice says the data is behind, and the state leaves the cross-state ranking on the home page.
• Over 7 days: return per $1 and ranks are hidden for that state until it updates.

Every game page links to the game's own page on the official lottery site. The lottery's records govern every prize and claim, so check there before you buy. See Responsible play for help and limits.