La Partage halves the house edge on eligible even-money bets at a standard single-zero roulette table. It does not halve every player's expected cost of playing: doubling the amount wagered cancels that mathematical advantage. The useful comparison is the rule together with your stake and the number of bets, not the percentage in isolation.
This guide works through a €10 red bet, then compares four hypothetical sessions. It is a rule-and-probability analysis, not a prediction, a table recommendation or a claim that a particular game is currently available on CasinOK.
What happens to a €10 bet when zero lands?
The rule used here is a 37-pocket wheel with one zero and a conventional 1-to-1 payout on red. With La Partage, zero returns half the eligible stake immediately. Evolution's French Roulette description confirms that half-loss rule for even-money bets. The calculation below assumes a fair wheel with equally likely pockets and independent spins.
| Outcome of the spin | Number of pockets | Cash returned from a €10 red bet | Net result |
|---|---|---|---|
| Red | 18 | €20: your €10 stake plus €10 profit | +€10 |
| Black | 18 | €0 | −€10 |
| Zero, with La Partage | 1 | €5 of your original stake | −€5 |
The €5 refund is not a €5 win. You began the bet with €10 and finish it with €5. On an ordinary single-zero table without this rule, zero would instead lose the entire €10.
Nor does the refund turn zero into a red result. Red still occupies 18 of the 37 pockets: a profitable red bet has a probability of 18/37, about 48.65%, under both sets of rules. The improvement is the smaller loss on one outcome, not a more accurate prediction of the next colour.
The edge, calculated from all 37 outcomes
Add the net results, weighted by their pocket counts, and divide by 37:
La Partage: [(18 × €10) + (18 × −€10) + (1 × −€5)] / 37 = −€5/37, or approximately −€0.1351 per €10 bet.
Ordinary single zero: [(18 × €10) + (19 × −€10)] / 37 = −€10/37, or approximately −€0.2703 per €10 bet.
Divide each expected loss by the €10 stake and the house edges are 1/74, approximately 1.35135%, and 1/37, approximately 2.70270%, respectively. We retain those exact fractions for the comparisons below and round the final money amounts to cents.
This is an average over possible outcomes, not a deduction the casino makes from each bet. Your next €10 bet can produce a €10 profit, a €10 loss or a €5 loss; it cannot settle as a 13.51-cent loss under these rules. Even a much longer session can finish far away from its mathematical expectation.
Where the saving disappears: stake and number of bets
For the fixed examples below, expected loss equals stake per bet × number of bets × house edge. Total money wagered counts every paid bet, including money staked again after a win. It is not the amount deposited or the amount left in the account.
| Hypothetical setup | Stake per bet | Paid bets | Total wagered | Expected loss |
|---|---|---|---|---|
| Ordinary single zero | €10 | 60 | €600 | €16.22 |
| La Partage, same exposure | €10 | 60 | €600 | €8.11 |
| La Partage, twice the stake | €20 | 60 | €1,200 | €16.22 |
| La Partage, twice the stake and bets | €20 | 120 | €2,400 | €32.43 |
Only the first two rows hold exposure constant. In the third row, doubling the stake cancels the halved edge. The last row has a better percentage but twice the expected money loss of the first row because four times as much money is wagered.
The bet counts are chosen examples, not measured speeds of any provider's table. For a fixed period, a faster table can increase the number of bets if you participate in every round; it does not require you to do so. If the available minimum exceeds the amount you intended to risk, a lower edge is not a reason to raise that amount.
The exact break-even comparison is simple: with all these rules unchanged, La Partage reaches the ordinary table's expected loss at twice its total wagering volume. That is an explanation of exposure, not a target to use up. A spending limit should reflect money you can afford to lose, not the much smaller expected-loss number in this table. Stop at your limit rather than increasing stakes to recover a loss.
The half-return does not cover every outside bet
Eligible even-money groups are red/black, odd/even and 1–18/19–36. Dozens, columns and single-number bets do not receive the half-return: being an outside bet does not imply eligibility. Wizard of Odds' roulette rules analysis explains these distinctions.
Therefore a mixed bet needs a separate calculation for each part. If you place €10 on red and another €10 on one number, you have exposed €20, not €10, and cannot apply the 1.35% rate to the whole amount. Keep the comparison to the bets the rule actually covers.
En Prison: returned stake is not a normal win
En Prison can leave an eligible stake on the table after zero. If the next resolving result favours that bet, the original stake returns without the usual profit. A €10 red stake released after a red result returns €10, not €20.
Repeated zero matters. If the stake waits for red or black, the expected loss matches La Partage. If another zero loses the imprisoned stake, it does not. Other rules use further levels of imprisonment. The same mathematical reference documents these differences. This guide's session table uses an immediate half-return, not a prison variant.
A useful rule, within a fixed budget
Before comparing two tables, establish four things: the wheel has one zero; your chosen bet qualifies; zero refunds half immediately; and the stake and number of bets stay within your original limits. If any condition changes, the comparison changes with it.
La Partage is a genuine improvement to the specified payout rule. It leaves the next spin unpredictable, retains a house edge and gives no protection against a run of ordinary losing bets. Its advantage is most clearly understood by holding exposure constant—not by spending more because the percentage looks smaller.
