Bankroll Duration Simulator
Enter your bankroll, bet size and pace to see what a session costs on average, and how far a single night can swing either way.
What the simulator does
First it works out the expected loss, which is plain arithmetic: house edge × bet size × number of bets. Then it plays 2,000 sessions with your settings and shows how the results are spread, from a bad night to a good one. A session stops early if you can no longer cover a bet.
To keep things simple, every bet is an even-money bet whose win chance matches the house edge you enter. With an edge of h, the chance of winning each bet is (1 − h) ÷ 2. At 2.7% that is 48.65%, the same as a red/black bet on a single-zero wheel. Games with big jackpots or long-shot payouts, like slots, swing much more than this, so treat the spread here as the calm version.
A worked example
With the default numbers you place 60 × 2 = 120 bets of $10, so $1,200 goes across the table. At a 2.7% edge the expected loss is 0.027 × $1,200 = $32.40, or $16.20 an hour. One session still varies a lot: the standard deviation of 120 even-money bets is about $10 × √120 ≈ $110. That is why plenty of individual nights end ahead while the average keeps drifting down. Play more hours and the expected loss grows in a straight line, while the swings grow only with the square root, so over time the edge wins out.
The same session at different house edges
Keep the default session (120 bets of $10, so $1,200 wagered) and change only the edge. The figures come from our house edge & RTP reference.
| Game | House edge | Expected loss, 2 hours | Per hour |
|---|---|---|---|
| Blackjack, basic strategy | ~0.5% | $6.00 | $3.00 |
| European roulette | 2.70% | $32.40 | $16.20 |
| American roulette | 5.26% | $63.12 | $31.56 |
The swings are about the same in all three rows, roughly $110 either way for 120 even-money bets. The edge is what decides where the middle of that range sits.
How pace changes the cost
The edge is charged on every bet, so a faster game costs more per hour even when the edge is the same. Change bets per hour from 60 to 100 and keep everything else: two hours is now 200 bets and $2,000 wagered, and the expected loss at 2.7% rises from $32.40 to $54.00. Nothing about the game got worse; you just played more of it. Slowing down, taking breaks and skipping side bets all cut the bet count.
Reading the results
- Expected loss: the long-run average cost of the session. It comes from the formula, not the simulation, so it does not change when you run it again.
- Simulated average result: the average of the 2,000 simulated sessions. It should sit close to the expected loss; small gaps are random noise.
- Bad night, typical night, good night: one session in ten ends below the 10th percentile and one in ten ends above the 90th. The median is the middle result.
- Sessions that finished ahead: winning nights are common in short sessions. That is how a game with a house edge still feels beatable.
- Sessions that ran out of money: the share of sessions where the bankroll could no longer cover a bet before time was up.
What the simulator leaves out
Every bet here is an even-money bet. Slots, keno and long-shot bets pay rarely but big, so the same edge gives much wider swings: more sessions end broke and a few end far ahead. Treat the spread shown here as the calm case. The slots RTP and variance guide explains why. The simulator also assumes a fixed bet size; if you raise your bets when you are losing, the expected loss grows with every dollar added.
Using it well
- Lower the edge or the pace and see how much longer your money lasts. Picking a lower-edge game usually saves more than any betting trick.
- If the “ran out of money” figure is high, your bet is too big for your bankroll. Our bankroll management guide suggests sizes.
- Decide your loss limit before you play. See setting limits.
Sources
Reviewed by Greg Parsons, editor, against the sources above.