Single-column probability is 32.43% on the European wheel and 31.58% on the American wheel. The payout is always 2 to 1. The math below explains exactly why the house keeps 2.70% on one wheel and 5.26% on the other.
The probability calculation
A column covers 12 numbers out of the wheel's total pocket count. The wheel pocket count is the entire denominator - the zeros are not excluded, because if the ball lands on zero, you lose your column bet.
- European wheel: 12 / 37 = 32.4324%
- American wheel: 12 / 38 = 31.5789%
That two-thirds-of-a-percent probability gap between the wheels - 0.85 percentage points - is the entire difference between a 2.70% and a 5.26% house edge. The American 00 nearly doubles the cost of every spin.
The payout calculation
A column bet pays 2 to 1, meaning a winning $10 wager returns $20 in profit. Your original $10 stake also stays on the felt; total return is $30. This payout is identical on European, American, and live-dealer wheels.
If the column loses, the dealer sweeps your chips and you lose the entire wagered amount.
Expected value and house edge
Expected value (EV) per dollar wagered on a European column:
You lose 2.70 cents per dollar wagered on average. Multiply by 38 instead of 37 pockets and the American EV drops to −$0.0526 per dollar - the canonical 5.26% house edge.
Comparison to other 2:1 bets
The dozen bet - 1 through 12, 13 through 24, or 25 through 36 - covers exactly 12 numbers and pays exactly 2 to 1. Probability is identical to the column on both wheel types. Read the comparison in Dozen vs Column.
Six-line (or "double street") inside bets pay 5 to 1 across 6 numbers - a different payout/probability profile, but mathematically equivalent house edge.
True odds vs paid odds
Fair "true odds" for a 12 / 37 outcome would pay 25 : 12, or about 2.083 : 1. The casino pays 2 : 1 instead. That gap - the missing 0.083 - is where the house edge lives.
On the American wheel, true odds are 26 : 12, or 2.167 : 1. The casino still pays 2 : 1. The bigger gap is why the American house edge is twice the European.
Quick-reference odds table
| Wheel | Pockets | Hit Probability | Payout | True Odds | House Edge |
|---|---|---|---|---|---|
| European (single zero) | 37 | 32.43% | 2 : 1 | 2.083 : 1 | 2.70% |
| American (0 & 00) | 38 | 31.58% | 2 : 1 | 2.167 : 1 | 5.26% |
What this means for your bankroll
At a $10 base unit on a European column, plan to lose roughly $0.27 per spin in expectation. Over a 100-spin session, that's $27 of expected loss - but the variance band is roughly ±$60 one standard deviation. Most short sessions end up or down by $30–$60. Long sessions converge toward the expected loss.
For a structured approach to managing that bankroll, see Low-Risk Column Grind and run the Probability calculator for your own stake size.
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