La Partage and En Prison Explained: The Roulette Rules That Halve the House Edge on Even-Money Bets
Most roulette players know the single zero costs them 2.7 percent on every even-money bet. Fewer know that some European and French tables quietly cut that cost in half with a rule called La Partage or En Prison. This guide explains how each rule works, what it does to the house edge, and how to spot it before you sit down.
What Happens to Even-Money Bets When the Ball Lands on Zero
On a standard European wheel there are 37 pockets: the numbers 1 to 36 and a single green zero. A bet on red, black, odd, even, low or high pays one to one, yet it covers only 18 of the 37 pockets. The zero belongs to nobody, so when it hits, every even-money bet normally loses. That one pocket is the whole source of the 2.7 percent house edge on those bets. La Partage and En Prison soften exactly this moment and nothing else.
How La Partage Works
La Partage is French for "the sharing". When the ball lands on zero, an even-money bet is not lost in full. The casino returns half of the stake and keeps the other half. Bet 10 units on red, see zero, and you get 5 units back. There is nothing to decide and no second spin, so it is the simplest of the two rules to follow at the table.
How En Prison Works
En Prison means "in prison". After a zero, the even-money bet is not collected. It stays on the layout, locked for the next spin. If your original bet wins on that spin, the stake is released and returned to you without any profit. If it loses, the stake goes to the house. Some casinos add a detail for a second zero in a row, either keeping the bet imprisoned again or moving to the La Partage half refund, so the exact procedure is worth asking about. Many French-style tables use a small marker on the layout to show which bets are imprisoned.
What the Rules Do to the House Edge
The arithmetic is short. Zero appears once in 37 spins on average, and La Partage refunds half the stake when it does. The expected loss per bet is therefore half of 1 in 37, which is 1.35 percent. En Prison reaches the same figure when the imprisoned bet is settled by one further spin, because the returned stake has an almost even chance to survive. Put that next to the plain single-zero edge of 2.7 percent and the double-zero edge of 5.26 percent, and these rules halve the cost of an even-money bet on a European wheel. Our breakdown of roulette odds on European and American wheels shows where each of those numbers comes from.
Where the Rules Apply and Where They Do Not
Both rules cover only even-money outside bets. A straight-up number, a split, a corner or a dozen still carries the full 2.7 percent edge on a single-zero wheel, because those bets simply lose when zero appears. The rules are also not universal. They are traditional in French roulette and appear at some European casinos, while many tables in other regions do not offer them at all. Double-zero American wheels rarely have a surrender rule, and where one exists it is usually less generous than the French versions, so never assume it. Check the posted table rules or ask the dealer before you buy chips.
How to Check for the Rule Before You Play
Look at the table layout and the sign beside the wheel. French-style layouts often show the words "La Partage" or "En Prison" near the even-money boxes, and a single-zero wheel with a French layout is the best sign. If nothing is posted, ask a floor supervisor how an even-money bet is treated on zero. Rules can also differ between a live table and an electronic version of the game, so confirm each one separately. Because details change between venues and over time, treat any figure here as a guide and verify the current rule on site.
What It Cannot Do
Halving the edge is a real improvement, but it does not turn roulette into a winning game. A 1.35 percent expected loss is still a loss, and over a short session luck will swamp the difference. The rule also does nothing for staking plans: as our guide to the Martingale and other betting systems explains, no pattern of bet sizes can change a negative expectation. The sensible use of La Partage is simple. Prefer a table that offers it, keep your stake steady, and stop when your budget is gone.
To compare other games by their cost, see the house edge by game overview or browse all of our casino game guides.
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