Bankroll & Budget Calculator

This is a budgeting tool, plain and simple. Tell it how much you're prepared to spend, your bet size and the game, and it simulates thousands of sessions to show how long that money typically survives, how often it runs out completely, and what you'd expect to lose along the way. There's no system here and no edge to be found — just a clear-eyed look at how the house edge grinds against a fixed budget over time.

I'd rather you used this before you play than learn it the hard way. The single most useful habit in casino play is deciding your limit in advance and walking away when it's gone. This tool turns that abstract advice into real numbers so the decision is easier to keep.

The chance your bankroll lasts is how often, across the simulations, you still had funds when your chosen session ended. The risk of losing it all is the mirror of that — the share of runs that hit zero before the end. Expected loss is the average amount gone by the close of the session, and it tracks closely with stake × spins × house edge. The typical end balance is the middle outcome, the result you're most likely to land near. If the risk of ruin looks high, the fix is mechanical: lower your bet, play fewer rounds, or pick a lower-volatility game — and adjust the inputs to see each lever work.

How long a budget really lasts

The blunt rule is that your bankroll divided by your average loss per spin gives a rough session length — but volatility scatters real sessions widely around that figure. A €100 budget at €1 a spin on a 96% RTP slot loses about 4c per spin on average, so the maths suggests roughly 2,500 spins of play. In practice some sessions end in twenty minutes and others run for hours; that variance is the whole point of seeing a range rather than a single number.

The two inputs you control most directly are bet size and number of spins. Halve your bet and you roughly double how long the same money lasts. Decide your session length up front, and you can size your bet so the budget is built to cover it — rather than topping up when it runs dry, which is exactly the moment to stop.

Setting limits that actually hold

A stop-loss is the amount you're willing to lose before you finish for the day; a win goal is a level at which you bank what's there and walk. The calculator lets you set both, and seeing how often each is reached makes them concrete rather than aspirational. The hard part was never knowing the limit — it's honouring it once you're in the moment, so set it here while you're calm.

Most licensed casinos let you set deposit, loss and session limits directly in your account, and these are the most reliable guardrails because they hold even when willpower doesn't. If gambling has stopped being fun, or you're chasing losses, free and confidential support is available in Ireland from Problem Gambling Ireland (problemgambling.ie) and the Gambling Awareness Trust. There's no shame in using it. 18+.

Worked example: €150 budget for a Friday session

You set aside €150 for the evening, plan to bet €0.50 a spin on a medium-volatility slot returning 96%, and want to know if it'll see you through a 500-spin session. Expected loss is straightforward: 500 spins × €0.50 × 4% edge ≈ €10. So on average you'd expect to finish around €140.

But the average hides the spread. The simulation shows a typical end balance near €138, a good run finishing comfortably up around €200, and a bad run down to €70 or worse. The risk of losing it all over 500 spins at this modest bet is low — only a few percent — because the bet is small relative to the budget. Now raise the bet to €2 a spin and rerun it: expected loss jumps toward €40, and the risk of busting climbs steeply. That contrast is the lesson — bet size, not luck, is what decides whether a budget survives the night.

Glossary

RTP

Return to player — the percentage of total stakes a game is designed to pay back over the long run, e.g. 96% means €96 returned per €100 staked on average.

House edge

The casino's built-in advantage, equal to 100% minus the RTP; it's the average share of every euro staked that the operator keeps over time.

Volatility

How a game pays out — low volatility means small, frequent wins, while high volatility means rare but larger wins and wider swings.

Wagering requirement

The total turnover you must bet before bonus funds and their winnings become withdrawable, written as a multiple such as 35x.

Expected value (EV)

The average outcome of a bet or bonus across many simulated attempts, expressed in euro — positive means good value, negative means an expected loss.