A slot session plan sets three numbers before you play: how much you can afford to lose, how long you will play, and the bet size that makes the first two fit. The bankroll does not make the game fairer. It decides how long you get to play and how the evening ends. The odds that a bankroll lasts depend heavily on volatility: in our solved example, a 100-coin bankroll lasted through 300 spins 93% of the time on a steady game and only 46% of the time on a volatile game with the same return.
This guide gives a step-by-step plan, the formula for an average session cost, the numbers on how often bankrolls run out, and what stop-loss and stop-win rules do and do not do. The calculations are our own, from two small machines solved exactly, and the safer play points link to our toolkit pages.
What is a bankroll for a slot session?
A bankroll is the money you set aside for one session of play, and nothing else. It is a fixed amount you can afford to lose entirely, held separately from rent, bills and savings. Once it is gone, the session is over.
A bankroll serves one purpose: it caps the cost. Slots have a negative expected value, so a bankroll cannot be “grown” by good management. It can only be spent over a chosen length of time, or lost sooner.
How do you work out the average cost of a session?
The average cost is a multiplication you can do in your head.
Average cost = bet per spin x number of spins x (1 minus RTP)
If you bet $1, play 600 spins and the RTP is 83% (the New Jersey minimum), the cost is 1 x 600 x 0.17 = $102. At 95% it is $30. For a game of unknown RTP, use the legal floor as the cautious figure.
| Spins | Bet $0.50 | Bet $1 | Bet $2 |
|---|---|---|---|
| 200 | $17 | $34 | $68 |
| 600 | $51 | $102 | $204 |
| 1,200 | $102 | $204 | $408 |
The figures are averages. They tell you what you should expect to pay in the long run, and your budget should be larger than the average, because volatility can make a session cost several times more.
How often does a bankroll run out?
We tracked the balance spin by spin on two invented machines, both returning 87.6%. Steady pays small amounts often, and Volatile pays large amounts rarely. We bet 1 coin per spin and asked how often the bankroll hit zero before the session ended. (Our how to choose a slot guide describes both machines.)
| Starting bankroll and number of spins | Steady runs out | Volatile runs out |
|---|---|---|
| 100 coins, 300 spins | 7.0% | 53.7% |
| 100 coins, 600 spins | 43.1% | 78.5% |
| 50 coins, 300 spins | 52.5% | 81.7% |
Three lessons come out of it.
- Average cost is not the whole story. Both machines lose 12.4 coins per 100 spins on average, so 300 spins costs 37.2 coins on average. A 100-coin bankroll is nearly three times that, and on Volatile it still runs out more than half the time.
- A bankroll that is too small for the game ends the session early. Halving the bankroll to 50 coins made Steady run out in half of 300-spin sessions.
- Lower volatility stretches a bankroll. If your aim is to play for a set time, a steadier game or a smaller bet is the lever.
How do you pick a bet size?
Work backwards from the time you want to play. This is a three-step method.
- Decide the length of the session. For example, 90 minutes at 600 spins an hour is 900 spins.
- Decide the amount you can lose. For example, $60.
- Choose the bet so the session cost fits with room to spare. At an 83% return, the average cost of 900 spins at $0.25 is 0.25 x 900 x 0.17 = $38. At $0.50 it is $77, which is more than your budget on average.
The bet of $0.25 leaves a margin of $22 above the average, and that margin covers part of the volatility. A higher-volatility game needs a bigger margin. A rough rule is to want a bankroll at least two to three times the average cost for a low-volatility game, and more for a high-volatility one, in line with the run-out table above.
Treat that rule of thumb as a starting point, not a guarantee. A bankroll can still run out early on a bad run, and when it does, the plan has worked as intended: you stop.
What do stop-loss and stop-win limits actually do?
These limits are popular, and both are about behavior, not odds.
- A stop-loss is the point where you end the session because you have lost a set amount. Your bankroll is the stop-loss, in effect. It protects the rest of your money.
- A stop-win is the point where you end the session because you are ahead by a set amount. It feels sensible, but it does not change the long-run cost. It makes you leave while you are up, which is good for keeping a result. It does not make the machine more generous.
Neither rule changes the odds of a single spin. What they change is the shape of your results. With a stop-win, you lock in a share of your good sessions. Without one, many good sessions keep going and, on average, give back the gain.
A cautionary note: a stop-win rule works only if you follow it. Many players set a target and then raise it once they reach it. That turns the rule into a sliding scale and removes the protection.
How should you handle wins during a session?
Split a win between “play money” and “keep”. A common approach is to move part of a win out of your play balance immediately, in the form of cash or a cashed-out ticket, and keep playing with the rest. The part you cash out is no longer at risk.
This does not alter the expected value of the money still at risk. It simply makes sure a lucky run leaves some trace, and it reduces the chance of playing an entire win back by default.
A worked plan, start to finish
Here is a complete example with invented but realistic numbers, so you can copy the method.
- The goal: an evening of about an hour and a half on a machine you have not played before.
- The limit: $60, set aside in cash before leaving home, and nothing else.
- The pace: about 600 spins an hour, so 900 spins in 90 minutes. You can check this by timing 20 spins and multiplying.
- The return: unknown, so use the cautious legal floor of 83% for the cost estimate.
- The bet: $0.25 a spin. The average cost is 0.25 x 900 x 0.17 = $38.25, which fits inside $60 with room for a bad run.
- The check: if the total bet shown on the screen is higher than $0.25 because the game charges per line, lower the line bet until the total is $0.25.
- The stop: when the $60 is gone, or 90 minutes pass, whichever comes first. If you are ahead at either point, cash out and keep the ticket.
Notice what the plan does not contain. There is no step that depends on the machine’s behavior, because nothing about the machine can be predicted. Every decision is about your money, your time and your pace, which are the only things you control.
What mistakes ruin a session plan?
- Topping up. Adding money after the bankroll is gone turns a limit into a suggestion.
- Raising the bet to chase a loss. The average cost is proportional to the bet, so a bigger bet speeds up the loss.
- Playing longer when ahead and when behind. Both extensions increase the amount wagered.
- Ignoring the pace. Fast play multiplies the amount wagered per hour. A bankroll is spent by spins, not by minutes.
- Using money that has a job. Rent and bills are not part of a bankroll.
- Playing when stressed or tired. Limits are harder to keep. If gambling is a way to escape a problem, step back.
What tools help keep to the plan?
Use whatever makes the limit automatic. A fixed cash amount in your pocket is a limit. A phone alarm is a time limit. Many licensed operators offer deposit limits, session reminders and breaks, and many places offer self-exclusion. Our guide to self-exclusion and blocking tools explains how they work, and the Safer play toolkit collects them.
For the general method of setting a budget and a time limit, see our guide to setting a gambling budget and time limit. If gambling is causing harm, visit our get help page.
Slot machines are legal in some places and not in others. See is gambling legal where you live before you play.
Where should you go next?
To understand why no plan changes the odds, read how to win at slots. To see the swings behind these numbers, read slot machine myths. And for the basics of RTP and volatility, read how slot machines work.