Red/Black Roulette Strategy
Red/Black is the most popular roulette bet in the world. It pays 1:1, has a 48.65% hit rate on European, and is the default target for most progression systems.
It is also the cleanest baseline for testing strategies in the tester.
The bet
You bet on either red or black. If the ball lands on a number of your colour, you win 1:1. If it lands on the other colour or the green zero (or 00 on American), you lose.
Red has 18 numbers: 1, 3, 5, 7, 9, 12, 14, 16, 18, 19, 21, 23, 25, 27, 30, 32, 34, 36. Black has the other 18.
Hit probability
European: 18/37 = 48.65%. American: 18/38 = 47.37%. The gap from 50% is the house edge contribution from the zero(s).
Loss probability on European: 19/37 = 51.35%. This is the number every even-money progression has to overcome - and never quite does.
Why it is the default test target
- 1:1 payout makes bankroll math trivial.
- Highest hit rate among standard bets.
- Same hit rate as odd/even and high/low - all even-money outside bets are mathematically equivalent.
- Most published systems specify red/black as the example.
Common red/black strategies
Flat red/black: same bet every spin. Baseline.
Martingale on red: double after loss.
D'Alembert on red: +1/−1 unit.
Fibonacci on red: sequence progression.
Alternating red/black: switch colour each spin - mathematically identical to picking one and sticking.
Common myths
'Red is hot, bet red.' Streaks happen by chance. Past results do not affect future spins. See Common mistakes.
'After 5 reds, black is due.' Same fallacy. Each spin is independent.
'Red and black should balance out over a session.' Not necessarily - they balance over many sessions, not within one.
Net expectation
Across 1,000 spins of $10 flat red on European, expected loss is $270 - exactly 2.70% of $10,000 total wagered.
Win rate will be very close to 48.65%. Net result will be approximately −$270. Variance can push individual sessions hundreds of dollars either side.