RTP vs Variance Simulator
See how short sessions scatter around the long-run average. Same seed and inputs always replay the same draws. Not a forecast. 18+ only.
Amounts are shown in dollarsfor reading — the arithmetic is the same. This is not an operator’s settlement currency.
Enter the numbers above and press Run seeded simulation.
How this is calculated
Theoretical expected loss
rounds × stake × (100% − RTP)
Each simulated round
a win sized to the RTP, or nothing
Hit rate is 40%, 20%, or 10% for the low / medium / high teaching bands.
Session result
sum of round profit or loss
The seed makes the sequence replayable.
The long-run average alone is on the RTP and house-edge calculator. The sourcing contract is on the methodology page.
Worked example (hypothetical)
96% RTP, $1 stake, 100 rounds — expected loss before any simulation:
- House edge
- 100% − 96% = 4%
- Theoretical expected loss
- 100 × $1 × 4% = $4
Individual 100-round sessions in the model often finish well above or below that $4 average. That spread is the point of the simulator.
Assumptions and limitations
- Two outcomes per round, independent draws, mean return equal to the stated RTP.
- Hit rates are teaching labels, not published game statistics.
- This is education, not gambling, legal, tax, or financial advice.
Play within limits
Variance is not a reason to chase a loss or to treat a lucky seed as skill. If gambling is causing harm, use the responsible gambling page. 18+ only.
Frequently asked questions
Is this how a real slot or table game works?
No. It is a two-outcome teaching model: each round either returns nothing or a win sized so the average equals the RTP you entered. Real games have many prize tiers.
Why can a short session finish far from the expected loss?
Expected loss is a long-run average. A short session is dominated by variance. Finishing ahead or losing several times the average are both ordinary in the model.
If I change the seed, can I find a winning setting?
No. Changing the seed only replays a different draw from the same model. It does not change the house edge and is not a method.
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