Games · Slots

Slots: see exactly why the house wins

A real slot hides its odds. Ours shows them. This is an illustrative model of how RTP and variance actually work — nine machines from a 75% legal-minimum grinder to a 99% 'loose' one, every paytable open. Spin a funded balance, watch the long run converge on the exact RTP, and see why even the 99% machine loses you money over time. It is not a simulation of any real slot machine.

Credits $20.00

About the middle of the pack for a modern machine.

RTP94.0%
House edge6.0%
Hit rate37.5%
Net-win rate35.5%
Max win×150
VolatilityMedium

These figures are rounded for display and are exact for this illustrative model — not the odds of any real machine.

Pick your stake and spin.

Real slots engineer “near-misses” to feel close. Ours doesn't — a loss is a loss. Switch to Number to see exactly what was drawn.

Pick your stake and spin — you'll see exactly where your number lands.
Wagered$0.00
Returned$0.00
Net$0.00
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An illustrative model of how RTP and variance work — not the odds of any real slot machine. Real slots have undisclosed odds. Fun credits only, no real money. Notice that even the 99% machine is a net loss over time — that's the whole point.

How this simulation works
Rules modeled
An illustrative slot. Each spin draws one uniform random integer in [1, 1,000,000]; a fixed paytable of contiguous integer ranges maps that number to a payout multiplier (0 = no win, ×1 = stake back, higher = a win). Nine machines span 75% (the Nevada legal minimum) to 99% RTP, each with a distinct volatility. Stakes are $0.20–$5 in integer cents; payout = round(stake × multiplier).
Assumptions
Spins are independent and identically distributed — no memory, no machine that's 'due', no skill or strategy that changes the odds. This is NOT a model of any real slot machine: real slots use proprietary, undisclosed reel maths. Ours is fully open so you can see exactly why the house always wins over time. Fun credits only, no real money.
Mathematical basis
Every figure — RTP, house edge, hit frequency, net-win frequency, max win, and the volatility index (the per-spin return standard deviation) — is computed in closed form directly from the disclosed ranges and is exact for this defined model. With the 1,000,000-outcome space each target RTP is an exact integer ratio (e.g. 96% = 960,000/1,000,000). A build-time integrity test re-derives every machine's RTP from its ranges and fails the deploy on any drift; the Monte-Carlo Play and Lab only validate against these exact values, never redefine them.
Engine version
slots engine 1.0
Validation
84 unit tests — range resolution including the boundary integers, paytable tiling/validation, exact RTP/volatility against hand-computed fixtures, the build-time RTP verifier (with a planted-broken paytable that must fail), seeded determinism, integer-cent money, and safe-integer run bounds.
Last reviewed
Independently reviewed and PASSED (D-008). An independent reviewer re-derived every preset's RTP and volatility from the disclosed ranges, confirmed the outcome space tiles exactly, and verified the simulator's integer-cent accounting; the build-time integrity gate re-checks the figures on every deploy. Last reviewed 2026-06-29 (1 independent review pass).