Understanding Slot Machine Payback Percentages

by John Grochowski

Every slot player has tough days when the wins aren’t coming. And many a player has had the same thought: “How can they say these machines pay 90 percent when I’ve lost everything I’ve put in? Seems more like zero percent to me?”

That’s a leader among questions players ask about percentages and the slots. Others include the basic “How do they calculate slot payback percentages?” and the more esoteric “If state reports show higher casino win percentages on tables than slots, how can they say slot paybacks are lower than tables?”

Basic answers:

**Slot paybacks are calculated by dividing the amount paid to players by the amount wagered, then multiplying by 100 to convert to percent.

**You get a 90-percent return and still lose your whole buy-in because of the effect of re-betting winnings.

**Casino win percentages or hold percentages on slots and tables measure different things. The percentages on table games are based on buy-ins, while those on slots are based on wagers.

Let’s get into more detail, one at a time.

**How are slot payback percentages calculated?

Those you see in state gaming board reports or in magazines or websites that report how much casinos pay on slots are casino-wide averages.

If you see “Casino X paid 90.5 percent on slots in May,” it means that in that month 90.5 percent of all money wagered on all that casino’s slots combined was returned to players as winnings. If you see “Casino Y paid 95 percent on $1 slots,” it means 95 percent of the money wagered on dollar slots was returned as player winnings.

Slots: How payback percentages really work:

How can a machine take all your money and still pay 90 percent? How is a 90 percent payback on a slot somehow worse than a 20 percent hold on a table game?

For example, if players make $1 million worth of wagers at Casino Y’s dollar slots and they pay out $950,000, then you’d divide $900,000 by $1 million to get 0.95. Multiply that by 100, and you get 95 percent.

If you see a payback percentage for an individual slot machine, it’s usually a theoretical percentage. The odds of each game are set to drive results toward an expected average return, just as the odds of roulette, craps or any other table game are set to drive results toward expected averages.

A slot machine’s theoretical payback might be 92 percent, but that doesn’t mean it will return 92 percent every player, every day or even every month. There will be big jackpots that send a short-term return soaring, and there will be hot and cold streaks. Over hundreds of thousands of plays, the odds will drive the results to settle in near the expected average.

**If a given slot pays 90 percent, how can I leave with zero?

Players need to understand that any payout you receive counts on the payout side, even if you then lose it.

Let’s say you start with $100 and bet $1 a spin, and that for the first 100 spins you receive $90 in payouts. For the next 90 spins, you receive $80. Then you get a nice hit or two, and the next 80 spins take you back to $100. After that, you decline $10 each time — 100 spins for $90, 90 for $80, 80 for $70, 70 for $60, 60 for $50, 50 for $40, 40 for $30, 30 for $20, 20 for $10 and 10 with no return.

At the end, you haven’t made $100 worth of wagers. You’ve bet $820. And your return isn’t zero, it’s $720.

You’d had a slot machine payback percentage of ($720/$820)*100, or 87.8 percent.

It’s probably no consolation as you walk away having lost your entire $100, but the machine has paid something close to a normal percentage.

Sometimes we lose money a lot faster than that; sometimes we walk away without losing it all and sometimes we win. The total of all payouts and all wagers by the many who play the games lead to the overall payback percentage.

**How can the house edge be lower on tables and slots but the casino win percentage be higher on tables?

First off, let’s make clear that the casino win percentage is the inverse of the payback percentage. A game with a casino win percentage of 5 percent has a payback of 95 percent — per $100 wagered, the casino keeps $5 and the player gets $95.

Many states like to list win percentages in their statistical reports, where are geared toward casino operators and regulators.

There’s sometimes some confusion that comes with comparing win percentages that almost always are higher on tables than slots despite table games having lower house edges.

The key is that the win percentage on the slots measures something very different from that on the tables:

Slot win percentage measures the portion of money wagered won by the casino.

Table win percentage measures the portion of BUY-INS that is held by the casino.

The difference is important, because players don’t just bet their money once and leave the machine or table. They rebet their winnings again and again, until a relatively small buy-in has led to thousands of dollars worth of wagers.

Slot and table players alike rebet winnings, but on slots that’s all electronically monitored and the win percentage reflects the rebets. Casinos don’t have the same quality of information on table players, so they use buy-ins instead.

As noted earlier, when I slide $100 into the bill validator on a slot machine. I win on some spins, lose on more, and continue to play. Let’s say I’ve had about average luck on a dollar machine, and before I lose my $100, I’ve had enough winning spins to make $2,000 in wagers. In the end, I lose 100/2,000ths, or 5 percent, of my total wagers. That 5 percent is the slot win percentage for my play.

Now let’s say I sit down at a blackjack table, and push $100 across the layout to the dealer, who then gives me $100 in casino chips. I bet $5 a hand, and I win some and lose a little more. A couple of my $5 chips bring smaller denomination tokens when I win 3-2 payoffs on blackjacks. I stick around to replay my winnings until I’ve made $2,000 worth of bets, and find I’ve lost $14. So I go to the cage to cash in $86 worth of chips.

What is the casino’s hold on my table action? It’s $14 of my $100 buy-in, or 14 percent.

Both at the slot machine and at the table, I’ve bought in for $100 and made $2,000 worth of wagers. On the slots, I’ve blown the full $100, while at the table, I’ve lost only $14.

My table results sure look a lot better than my slot results, don’t they? But the win percentage would show that the casino kept 14 percent at the table, and only 5 percent on the slot.

Bottom line: Table games can have a lower house edge than slots and still have a higher casino win percentage just because slots and tables are measured differently.

John Grochowski has been covering casinos and casino games for nearly 40 years. He is the author of six books
and his work appears in newspapers, magazines and websites around the world.

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