Roll (Roulette) Odds Calculator
Green-in-N odds, streak probabilities and expected loss. Updates live as you type.
Martingale = double after every loss. The last figure is the total staked across the streak — the amount you'd need in balance to place the next double.
| Rounds | P(no green) | P(≥1 green) |
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The maths behind Roll
Roll is a 15-slot wheel: 7 red, 7 black, 1 green. Red and black pay 2× on a 46.67% chance, green pays 14× on a 6.67% chance. Every colour returns 93.33% — a 6.67% edge — so the expected loss over N rounds is just bet × N × 0.0667, whatever you pick.
Green "is due"
It isn't. The chance of no green in 15 rounds is 35.5%; in 30 rounds, 12.6%; in 50, 3.2%. Long green droughts are normal and tell you nothing about the next spin. The table on the right shows exactly how often you'd sit through them.
Martingale
Doubling after every loss on red looks safe until the streak arrives. Five straight losses happen 4.3% of the time on any given five-round window — roughly once every 23 rounds — and cost 31 base bets. Ten straight losses (0.19%, or once per ~530 rounds) cost 1,023 base bets. The strategy converts many small wins into one catastrophic loss; the expected value is unchanged at −6.67%.
What's the probability of green on CSGORoll?
1 in 15, or 6.67%, on every single spin regardless of history.
How often does red lose 10 times in a row?
(8/15)^10 = 0.19% for any given run of 10 spins. Over a long session you will see it.
Is there a winning Roll strategy?
No betting pattern changes the −6.67% expected return per coin. Strategies only change the shape of the variance.
Where can I play Roll for real?
CSGORoll is the original. Code GETBOX adds a 10% bonus and 3 free cases — but the edge is the same 6.67% there.
Worked example: chasing green for 50 rounds
◎10 on green, 50 rounds: wagered ◎500, expected loss ◎33.35. Expected number of greens 3.33; chance of none at all 3.2%; chance of at least one 96.8%. Each green pays ◎140, so three greens return ◎420 on ◎500 — the typical session ends down ◎80 despite 'hitting' three times.
Common mistakes
- Believing a colour is 'due' after a streak. Each spin is independent.
- Sizing a martingale to survive 5 losses when 10-loss streaks occur every ~530 rounds.
- Comparing colours by 'hit rate' rather than expected return — all three are 93.33%.
Other calculators
Try the maths live
Every number here can be tested with fake coins: case opening, Roll, Upgrader, Crash.
- House edge
- The share of every wager the operator keeps over the long run. 1% edge = ◎10 expected loss per ◎1,000 wagered.
- RTP
- Return to player — the mirror of house edge. 90% RTP on a case means a 10% edge.
- Expected value (EV)
- What a bet is worth on average: sum of (payout × probability). Always below the stake on a real site.
- Variance
- How much results swing around the average. High variance = long dead runs, rare big hits.
- Provably fair
- A seed-hash system letting you verify a result was fixed before your bet. Proves honesty, not good odds.