French roulette odds and La Partage

What La Partage changes

Red/black, odd/even and low/high bets are the eligible even-money groups in this model. A normal win pays 1:1. An opposite result loses the stake. Zero loses half rather than all of it.

The 1.35% calculation

For a $10 red bet: 18 outcomes earn $10, 18 lose $10 and zero loses $5. Expected net is −$5/37, or about −$0.1351. Dividing by $10 gives 1/74, or 1.351351%, house edge.

Other bets keep their normal treatment

The half-loss rule does not automatically apply to straight-up bets, dozens or columns. A standard single-number wager still has its usual 2.70% edge on the 37-pocket wheel.

En Prison needs its own rules

En Prison can hold an eligible stake over to a later spin instead of immediately returning half. The treatment of another zero must be specified. This package does not model that deferred settlement in the calculator.

House edge with and without La Partage

French roulette table terms

Rouge / Noir

Red / black

Pair / Impair

Even / odd

Manque / Passe

Low 1–18 / high 19–36

Douzaine / Colonne

Dozen / column

Plein

Straight-up on one number

Cheval

Split

Transversale pleine

Street

Carré

Corner

Sixain

Six-line

A French layout uses the same 37-pocket wheel as European roulette. The European roulette odds apply unless a written rule such as La Partage changes settlement.