Put a casino bonus's terms in and the calculator gives you three numbers: how much you have to bet before the bonus turns into cash, how much of that betting the house keeps on average, and what the bonus is worth once you subtract it. Load one of the real offers below or type in your own.

The short version of what it shows: a bonus is worth claiming when the betting it asks for loses less, on average, than the bonus pays. A $1,000 match at 15x on the bonus, cleared on a 96% slot, asks for $15,000 of spins that lose about $600 - so it is worth about $400. The same $1,000 at 15x on deposit plus bonus asks for $30,000 and loses about $1,200, so on average it costs you $200 to take it.

The formula, in four lines

Every result comes from four lines of arithmetic. You can do them on a phone calculator with the terms page open.

Step Formula $1,000 bonus, 15x on the bonus, slots at 96%
1. Wagering the terms ask for multiple x (bonus, or deposit + bonus) 15 x $1,000 = $15,000
2. Real bets on your game step 1 / the game's weighting $15,000 / 100% = $15,000
3. Expected loss while clearing step 2 x (100% - RTP) $15,000 x 4% = $600
4. What the bonus is worth bonus - step 3, no more than the max cashout $1,000 - $600 = +$400

Step 1 is where most players go wrong. "15x" on the bonus and "15x" on deposit plus bonus look identical in an ad and differ by the whole deposit. On a $1,000 match the first is $15,000 of betting and the second is $30,000. The terms say which; the word to look for is "deposit" next to the multiple. Our 30x explainer goes through how to tell from the wording.

Step 2 is where the game you like matters. Operators credit only part of each bet on some games. At BetMGM New Jersey a dollar on slots counts as a dollar, a dollar on video poker or live dealer as 20 cents, and a dollar on non-live blackjack as 10 cents, which is why its 15x behaves like 150x at the blackjack table. An excluded game counts nothing at all.

Step 3 uses the game's return to player (RTP). A slot paying back 96% keeps 4 cents of every dollar over the long run. Most regulated US slots publish an RTP between about 92% and 97% in the game's help screen; use the one for the game you will actually play. A lower RTP makes the same bonus more expensive to clear.

Six real offers through it

The same four lines on offers we have taken apart. All assume a 96% slot unless the row says otherwise; terms as published when we read them (see each teardown for the date).

Offer Turnover Expected loss Worth, on average
BetMGM NJ $25 on the house, 1x $25 $1 +$24
Borgata NJ 100% to $500, 5x on the bonus $2,500 $100 +$400
BetMGM NJ 100% to $1,000, 15x on the bonus $15,000 $600 +$400, if you can bet $1,071 a day for 14 days
BetMGM NJ $1,000 on blackjack (10% weighting, 99.5% RTP) $150,000 $750 +$250, but at $10,714 a day
Any $100 match at 30x on deposit + bonus $6,000 $240 -$140
Caesars $1,000 match, 15x on deposit + bonus $30,000 $1,200 -$200

Two things stand out. First, a low multiple on a smaller bonus often beats a big headline: Borgata's $500 is worth as much as BetMGM's $1,000 for a sixth of the betting. Second, the deposit-plus-bonus offers lose money on average even before the clock runs out. Sources: BetMGM, Borgata, Caesars.

What the number leaves out

The calculator gives the average over many players. Your one attempt will land somewhere else, and the terms add rules the arithmetic can't see.

Most players don't finish. On a sticky bonus your deposit is locked in with the bonus until the wagering clears. Spin $15,000 through a slot and a large share of players hit zero along the way; the average is held up by the few who win big. If losing the deposit would hurt, the average is the wrong number to look at - the deposit is.

Max cashout caps the upside. Many no-deposit offers cap what you can withdraw from them ($100 to $150 at FanDuel, Borgata and BetMGM when we read them). The calculator caps the value at the figure you enter.

The clock. Divide the real bets by the days you have. $15,000 in 14 days is $1,071 a day; if that is more than you play, the bonus expires with part of it unspent and the value is lower than shown.

Max bet and excluded games. Terms commonly cap the size of a bet while a bonus is active and list slots that don't count. Breaking either can void the bonus and its winnings. These aren't in the arithmetic: read them before your first spin. Our guide to the catch in low wagering bonuses lists what to look for.

It is not a way to make money. A positive number means the bonus offsets part of the house edge on play you were going to do anyway. It doesn't make gambling pay. Set a limit before you deposit; if it stops being fun, call or text 1-800-MY-RESET.

Questions people ask

Multiply the bonus (or the deposit plus the bonus, if the terms say so) by the multiple. A $200 bonus at 20x is $4,000 of qualifying bets. Then divide by the weighting of the game you play: on a game that counts 20%, it's $20,000 of real bets.

On the bonus only and cleared on slots, 15x is at the friendly end of regulated US offers: at a 96% RTP it costs about 60% of the bonus, so you keep roughly 40% of it on average. On deposit plus bonus the same 15x doubles the betting and usually loses money on average.

At 96% RTP, 30x on the bonus costs 120% of the bonus on average, so the bonus is worth less than nothing before caps and clocks. Below 25x on the bonus only is the rough break-even point on a 96% slot.

Only if the terms say deposit plus bonus (sometimes written D+B). BetMGM NJ's match counts the bonus only; Caesars' deposit match counts both. Look for the word deposit next to the multiple.

The RTP of the game you will clear it on, from the game's help or info screen. If you don't know, 96% is typical of a regulated US slot; video poker and blackjack played well are higher, but they usually count for less toward the wagering.