Roulette odds explained: streaks, due numbers and betting systems

Roulette looks simple, but most of what people believe about it is wrong. Numbers are not "due", streaks are not signals, and no betting pattern changes the maths.

This guide puts real numbers on the questions players ask most, all for a European single-zero wheel with 37 pockets, the kind used on All In. If you are new to the table, start with our guide to how to play roulette.

Every spin starts fresh

The wheel has no memory. On every spin each of the 37 pockets has the same 1 in 37 chance, whatever happened before. Red after five reds is still 18 in 37. A number that has not appeared for 100 spins is still 1 in 37.

Everything below follows from that one fact.

How long until my number comes up?

There are 37 pockets, so it is tempting to think your number will appear once every 37 spins. It often will not. Here is the chance a single number appears at least once:

How rare are streaks?

Streaks feel meaningful, but on a busy table they turn up all the time. The chance that the next few spins all land on red (or all on black):

Those odds are for a streak that starts now. Over a long session the chance that one appears somewhere is much higher. That is why every table eventually shows a long run of one colour, and why it tells you nothing about the next spin.

Why betting systems don't win

The best-known system is the Martingale: bet on red, and double your bet after every loss so the first win gets everything back plus one chip. It feels safe because you usually win a little.

The catch is the rare losing run. Lose seven spins in a row on red, which happens about 1 time in 106, and you have put in 127 chips to chase a 1-chip profit, with the next bet 128 chips. A run like that is likely to show up within a few hundred spins, and the table limit or your balance stops you before the win arrives.

• Martingale (double after a loss): many small wins, then one large loss.
• Reverse Martingale (double after a win): many small losses, occasionally one larger win.
• Fibonacci, D'Alembert and others: different patterns, same result.
• None of them change the 1 in 37 chance on each spin, so none of them change the long-run return.

The number that matters: 97.3%

On a single-zero wheel every bet pays as if there were 36 pockets, but there are 37. Over time that means each bet returns about 97.3% of what is staked, whether you play red, a dozen or a single number. The zero is the whole difference.

What changes between bets is the feel. Red or black wins almost half the time with small, steady results. A single number wins rarely but pays 35 to 1. Pick the one you enjoy; the long-run return is the same.

Quick answers

See it for yourself

The best way to get a feel for the odds is to watch them play out. Roulette on All In spins on our server with virtual coins only, so you can try a system, track a streak or wait for your number with nothing real at stake. 18+, coins have no cash value.