Slot Math
Search for bankroll advice and you get confident numbers: how many bets to keep in reserve, what your risk of ruin is, whether a bonus buy is worth it. Some of that is arithmetic anyone can check. The rest needs a figure the game providers do not publish. This page does the first part properly and refuses the second, which is the opposite of how the topic is usually handled.
Volatility is the number that would answer that, and nobody publishes it.
What your session costs, before variance touches it
| House edge100% minus the RTP | 3.50% |
| Expected cost per spinbet times house edge | RM0.035 |
| Expected cost per hourat your chosen spin rate | RM21.00 |
| Turnover before the bankroll is gonetotal stakes placed, on average | RM14,286 |
| Spins your bankroll supportson average, no bonus, no luck either way | 14,286 |
| Hours that representsat your chosen spin rate | 23.8 h |
Your inputs are kept in this browser so the numbers are still here when you come back. Nothing is uploaded.
Four figures that need nothing but multiplication
Every number in the table above comes from two inputs and one operation. There is no model, no assumption and no estimate in any of them.
All four hold regardless of the game's volatility, its features, its bonus round, or anything you do while playing. They describe the average of a very large number of spins, which is exactly what a session is not. That gap is the next section.
Risk of ruin, and why the honest answer is that we cannot tell you
The obvious next question is: what are the chances I lose the lot before I get anywhere. That figure has a name, risk of ruin, and it is genuinely computable. It needs three things: your bankroll in bet units, the house edge, and the variance of the game's payout distribution.
The first two are on this page. The third is not published.
Providers state an RTP. Almost none state a variance figure, and the volatility ratings that circulate as "high" or "medium" are usually adjectives copied between affiliate sites with no underlying number and no source. Across 47 Pragmatic Play titles read from the provider's own pages, not one carried a volatility figure. Across 24 providers tested, none served one in the markup either.
So a risk of ruin percentage on a slot page is one of two things: a figure computed from a variance number the writer invented, or a figure copied from someone who did. A precise-looking output built on a made-up input is worse than no output, because it travels further.
It does not change the cost, it changes the clock
Buying a feature for, say, 100 times your bet feels like a different kind of decision. On expected cost it is not one.
If the bonus buy runs at the same RTP as the base game, then paying 100x costs you 100 times the bet times the house edge, in expectation, in a single click. At RM1 and 3.50% that is RM3.50. Playing 100 ordinary spins at RM1 also costs RM3.50 in expectation. Identical expected cost, delivered in one spin instead of a hundred.
What changes is the rate. A hundred base spins take about ten minutes; the buy takes ten seconds. So the buy multiplies your cost per hour by roughly the same factor it compresses the time, and it multiplies your variance too. That is the whole trade, and it is a real one. It is just not the trade the marketing implies.
The only input in this entire page you control
Look back at the calculator. Bankroll, bet size and spin rate are yours. RTP belongs to the operator, which chose the configuration. Variance belongs to the provider, and is not disclosed to either of you.
Three of the five inputs that decide what a session costs are set before you sit down. A loss limit is the one lever that is entirely yours, and unlike everything else on this page it does not require knowing anything you cannot look up.
There is no version of this page that ends with a way to win. Every RTP figure available is below 100%, which means every game described here is built to return less than it takes. The arithmetic can tell you what that costs and how fast. It cannot turn the sign around.
Frequently asked
There is no honest single answer, because the figure that would produce one is the game's variance and providers do not publish it. What can be said exactly: a bankroll divided by the house edge gives the total turnover it supports on average. RM500 at a 3.50% edge supports about RM14,286 of stakes, which at RM1 a spin is roughly 14,000 spins. That is an average across many sessions, not a floor for yours.
Not computable from public information. Risk of ruin needs bankroll, house edge and the variance of the payout distribution. The first two are known, the third is not published by the providers. Any specific risk of ruin percentage you see on a slot page was calculated from a variance number that someone invented or copied. The direction is still reliable: risk rises as bet size rises relative to bankroll.
On expected cost it is neutral, provided the bonus buy runs at the same RTP as base play. Paying 100 times your bet costs 100 times bet times house edge in expectation, which is identical to playing 100 ordinary spins. What changes is speed and variance: the same expected cost arrives in one spin instead of a hundred, so your cost per hour rises sharply. Check the buy RTP in the game's information screen, because some titles run it lower than base play.
Bet size times house edge times spins per hour. At RM1 a spin, a 96.50% game and 600 spins an hour, that is RM21 an hour in expectation. Most players have never calculated this, and it tends to be the number that changes behaviour rather than the RTP percentage itself.
No. It does not change the expected cost of any spin you actually play. What it does is cap the worst case and remove the decision from the moment you are least able to make it well. Of the five inputs that determine what a session costs, three are set by the operator and the provider before you start. A loss limit is the one that is entirely yours.
Because every RTP figure available is below 100%, which means every game is designed to return less than it takes. No pattern of bet sizing, timing or game selection changes the sign of that. The arithmetic here tells you what the cost is and how quickly it accrues, which is genuinely useful, and it stops there because that is where the honest part stops.
Where each input in the calculator comes from
The calculator takes an RTP and a bet size and does the rest. Both of those come from somewhere, and both are worth checking rather than assuming.
47 Pragmatic Play titles with the provider's published RTP and the source link for each. Range 95.45% to 97.02%, which on a RM1,000 turnover is a spread of about RM15.70.
Providers ship many titles at several RTP configurations and the operator picks one. There is a log there for recording what your game's own information screen actually shows.
A wagering requirement is turnover you have committed to in advance. Above roughly 24x on a typical edge, the expected loss from clearing it exceeds the bonus, with a simulator that demonstrates the convergence.
Open a U88 account
Disclosure: this site is run by a U88 affiliate and earns a commission on accounts opened through the link above. It is worth noticing that a page telling you the expected cost per hour is negative also carries a link to open an account. Both are true. The arithmetic above does not change because of who published it, and every figure in it can be recomputed without us. U88's minimum deposit is RM30. 18+.