3 reds in a row: the odds — both of them
Two different questions hide in this query. A specific window: the next 3 spins all red = (18/37)3 = 11.514% (1 in 9). Your actual session: the chance of seeing a run of 3+ reds at least once is 100.0% in 100 spins, 100.0% in 200, and it’s practically certain — computed exactly with a Markov chain (method), a figure most sites never touch.⚙ computed
Will you see it? Session odds
| Session length | P(streak ≥ 3 at least once) | Expected count of such runs |
|---|---|---|
| 50 spins | 97.66% | 2.89 |
| 100 spins | 99.95% | 5.85 |
| 200 spins | 100.00% | 11.76 |
| 500 spins | 100.00% | 29.50 |
| 1000 spins | 100.00% | 59.06 |
Three in a row is bar-bet territory — with ~4.4 expected occurrences per 200 spins, an evening without one would itself be the anomaly. Treat it as wallpaper.
Why this streak matters: it’s a Martingale killer
Betting black through 3 reds on a $5 Martingale means your next bet is $40 and climbing. Our million-session Martingale run shows exactly how often these walls arrive.
The fallacy checkpoint
After 3 reds, the next spin is still red with probability 18/37 = 48.65%. The wheel has no memory — streaks are what independence looks like, not evidence against it. The 1913 Monte Carlo table famously ran 26 blacks while the room bet ever-heavier on red; the episode named the gambler’s fallacy — its place in the game’s full timeline here.
Other streak lengths
4 in a row5 in a row6 in a row7 in a row8 in a row9 in a rowodds hub →
Frequently asked
What are the odds of 3 reds in a row in roulette?
For a fixed window: (18/37)^3 ≈ 11.514% on a European wheel, about 1 in 9. On American wheels it’s rarer: (18/38)^3 ≈ 10.628%.
Will I ever see 3 reds in a row?
More often than intuition says: at least once in 100% of 200-spin sessions by exact Markov computation. Long streaks are a normal feature of independent spins.
After 3 reds, is black due?
No — each spin is independent, so black is still 48.65% (EU). Betting bigger on “due” colors is the gambler’s fallacy, and it’s exactly how streaks eat Martingale bankrolls.