A losing streak calculator shows how ordinary long losing runs are. On red at single-zero roulette, losing your next 10 bets is about 1 in 784. That sounds rare. Over 1,000 spins, though, there’s a 46% chance you’ll see a run of 10 or more somewhere. Free, exact maths, no simulation needed.
Losing streak calculator: two different questions
People mix these up all the time, and the gap between them is huge.
“Will my next 10 bets all lose?” That’s the small number. On red, the chance of losing a single spin is 19 in 37, about 51.4%. Ten in a row is 0.514 multiplied by itself ten times, which is 1 in 784.
“Will I see 10 losses in a row at some point tonight?” That’s the big number, because every spin is a fresh chance for a streak to start. Across a long session it stops being unusual.
| Red at roulette | Next bets all lose | Somewhere in 100 spins | Somewhere in 1,000 spins |
|---|---|---|---|
| 6 in a row | 1 in 54 | 60% | almost certain |
| 8 in a row | 1 in 207 | 20% | 91% |
| 10 in a row | 1 in 784 | 5% | 46% |
In a typical 200-spin session, the longest losing run on red is around 7. Run the calculator at 1,000 spins and it’s about 9.
Why this matters for your money
Streaks are where betting systems break. The Martingale doubles after every loss. Starting at £1, eight losses in a row means your next bet is £256, and you’ve already lost £255 to win back a single pound. The table above says eight in a row turns up in about one session in five of 100 spins. The Martingale calculator and betting systems simulator show it happening.
It’s also why bet size matters. If each bet is 10% of your budget, a run of 10 losses, which happens, wipes you out. At 1% it barely dents it.
The games in the list
- Roulette, red: 18 winning pockets out of 37, or 38 on a double-zero wheel.
- A dozen: 12 out of 37. You lose two times in three, so streaks come thick and fast. Five losses in a row is about 1 in 7.
- Blackjack: about 46% of hands that aren’t pushes are wins, with decent strategy.
- Baccarat Banker: about 50.7% of decided hands, ties left out.
- Coin flip or a true evens bet: exactly 50%.
Choose “Custom” for anything else. A 3.0 shot at the bookies with a fair chance of about 33% behaves much like a dozen at roulette.
The streak doesn’t make the next one more likely to win
After eight losses on red, the chance of the next spin winning is still 18 in 37. The wheel doesn’t owe you. That idea has a name, and a simulator of its own: the gambler’s fallacy simulator.
A long losing streak is when the urge to win it back is strongest. The chasing losses calculator shows what doubling up to recover really risks.