# Single-zero vs double-zero roulette: what changes?

Canonical HTML: [Single-zero vs double-zero roulette: what changes?](https://howtocasino.uk/guides/single-zero-vs-double-zero-roulette/)

Published: 2026-10-29
Updated: 2026-10-29
Publisher: HowToCasino
Language: en-GB
Topic: Roulette

## The short answer

Single-zero roulette has 37 pockets: 1–36 and 0. Double-zero roulette adds a separate 00 pocket, giving 38. Assuming equally likely pockets and conventional payouts, including 35:1 for a straight-up number and 1:1 for red or black, the extra losing outcome raises the house edge from about 2.70% to 5.26%. Modified payouts, special bets and zero-return rules need separate calculations.

![Two comparison panels show thirty-seven pockets with one zero and thirty-eight with zero and double zero; both use a 35-to-1 straight-up profit payout.](https://howtocasino.uk/illustrations/roulette-zeros.png)

Conventional fair-wheel model: 35:1 means £35 profit plus a returned £1 winning stake. The same £36 return is available against 37 or 38 equally likely pocket outcomes; special rules are excluded.

## What is the difference between a single-zero and double-zero wheel?

| Feature | Conventional single zero | Conventional double zero |
| --- | --- | --- |
| Common name | European roulette | American roulette |
| Pocket labels | 1–36 plus 0 | 1–36 plus 0 and 00 |
| Total pockets | 37 | 38 |
| Red / black pockets | 18 / 18 | 18 / 18 |
| Zero pockets | One | Two |
| Straight-up profit payout used here | 35:1 | 35:1 |

These are names for familiar configurations, not a substitute for the rulebook. A lobby label such as American, European, French, live or premium does not establish every payout and zero rule. This guide compares the conventional configurations in the table, assuming equally likely pockets and no additional wager or altered prize schedule.

The supporting operator descriptions are international product explanations. We have not tested a current GB table or checked that a particular operator offers every version. Use the actual game's help for its configuration and the operator's GB licence separately.

Sources:

- [European Roulette: international operator description and conventional payout table](https://www.pokerstars.com/casino/game/gdk-roulette-european/3200/1/) — PokerStars. Checked 2026-10-29.
- [American Roulette: international operator description, zero pockets and five-number wager](https://www.pokerstars.com/casino/game/american-roulette/3200/11/) — PokerStars. Checked 2026-10-29.

## Does 00 mean two zeros, and is zero covered by an even bet?

On the conventional double-zero wheel, 0 and 00 are separate single pockets. A straight-up bet on 0 does not win when 00 lands. Each individual pocket has probability 1/38 under the fair-wheel model; the two together account for 2/38, not two outcomes inside one pocket.

Zero pockets are outside the ordinary red/black, odd/even and 1–18/19–36 categories. Zero being an even integer in arithmetic does not make it a winning result for roulette's Even betting position. Read the game's defined groups rather than applying the everyday mathematical label.

Where the conventional full-loss rule applies, red loses on black and on the zero pockets. Adding 00 adds a losing outcome without adding another red pocket. A special zero-return rule changes that settlement and must be checked separately.

Sources:

- [American Roulette: international operator description, zero pockets and five-number wager](https://www.pokerstars.com/casino/game/american-roulette/3200/11/) — PokerStars. Checked 2026-10-29.
- [European Roulette: international operator description and conventional payout table](https://www.pokerstars.com/casino/game/gdk-roulette-european/3200/1/) — PokerStars. Checked 2026-10-29.

## How do the winning probabilities change?

| Wager under the stated model | Single-zero win probability | Double-zero win probability | Profit payout if it wins |
| --- | --- | --- | --- |
| One straight-up number | 1/37 ≈ 2.70% | 1/38 ≈ 2.63% | 35:1 |
| Red, covering 18 numbers | 18/37 ≈ 48.65% | 18/38 ≈ 47.37% | 1:1 |

Probability and payout answer different questions. The straight-up number is slightly less likely to hit on the double-zero wheel, while the conventional prize stays the same. Red covers many more outcomes than one number, but its prize is smaller. Neither probability is a forecast that a particular spin will win.

A 35:1 profit payout on a £1 winning stake means £35 winnings plus the £1 stake returned: £36 in total. A 1:1 win on £1 returns £2 in total. The returned stake is not extra profit, and a losing £1 wager returns £0 under this model.

> **35:1 profit is different from 35× total returned**
>
> Always establish whether a displayed multiplier includes the returned winning stake. The expected-value calculations below use a £36 total return from a £1 straight-up win.

## Why does the house edge rise from 2.70% to 5.26%?

For a £1 straight-up bet, the net result is +£35 on a hit and −£1 otherwise. Weight each net result by its probability; do not subtract the stake again after using a net-profit figure.

| Fair-wheel calculation | Expected net result per £1 staked | House edge |
| --- | --- | --- |
| Single zero: (1 × £35 − 36 × £1) / 37 | −£1/37 ≈ −£0.027027 | About 2.70% |
| Double zero: (1 × £35 − 37 × £1) / 38 | −£2/38 ≈ −£0.052632 | About 5.26% |

The same result follows for red at 1:1: single zero has eighteen +£1 outcomes and nineteen −£1 outcomes; double zero has eighteen +£1 outcomes and twenty −£1 outcomes. The extra zero creates a second unit of expected disadvantage across the equally weighted pocket outcomes.

The double-zero edge is close to twice the single-zero edge, but not exactly twice: the denominators differ. This comparison describes the two specified pay structures. It is not a house-edge calculation for every game or wager bearing the roulette name.

## Does a 2.70% edge mean a £100 session can only lose £2.70?

No. Under the stated model, £100 of total stakes has an expected net loss of approximately £2.70 on single zero or £5.26 on double zero. That is a mathematical average over the outcome distribution, not the result a session must produce. An individual can lose the whole amount committed.

Total stakes count every wager, including money won and staked again. They are not the original deposit, the current balance or the amount returned. A £20 deposit can support more than £20 of turnover through repeated play, while losses can also end the session quickly.

Our [RTP explainer](https://howtocasino.uk/guides/what-is-slot-rtp/index.md) develops the distinction between theoretical return, turnover and a personal result. Its slot examples illustrate the accounting concept; they do not supply the rules for this roulette comparison.

## What if you cover both red and black?

For an explicitly hypothetical illustration, put 50p on red and 50p on black, with conventional 1:1 profit payouts and full losses on zero. The total stake is £1. This explains the settlement; it is not a recommendation to place these bets.

| Wheel result | Total returned from the two bets | Net result on £1 total stake |
| --- | --- | --- |
| Red | £1 from the winning 50p red bet; £0 from black | £0 |
| Black | £1 from the winning 50p black bet; £0 from red | £0 |
| 0, or 00 on a double-zero wheel | £0 | £1 loss |

Most pocket outcomes now break even rather than produce a profit. The zero pockets still lose the full £1. The expected loss remains 1/37 of the total stake on single zero or 2/38 on double zero. Covering both colours has not removed the house edge.

Adding more wagers changes the total paid and settlement; it does not change which pocket wins. A results board or a run of red numbers does not establish that black or zero is due next under the independent fair-spin model.

## When do the usual house-edge figures not apply?

The American five-number basket is a useful exception. Where a wager covers 0, 00, 1, 2 and 3 and pays 6:1 profit, it wins on five of thirty-eight pockets. Its expected net result per £1 is (5 × £6 − 33 × £1) / 38 = −£3/38: about a 7.89% house edge, not 5.26%.

La Partage is a different exception. Where it returns half of an eligible even-money stake on a single zero, the red-bet model has eighteen +£1 outcomes, eighteen −£1 outcomes and one −50p outcome. The expected loss is 50p/37, giving about a 1.35% edge on that qualifying bet.

That does not change the chance of red landing, and it does not automatically halve the edge on straight-up numbers, dozens or columns. French branding alone is insufficient: check the qualifying bets and exact zero settlement. En Prison instead holds an eligible stake for later settlement; repeated-zero and release rules need their own reading.

Multiplier, jackpot and side-bet versions can change payouts or add costs while retaining a single-zero wheel. Counting pockets is therefore necessary but not sufficient. The actual table's complete payout and feature rules determine the comparison.

Sources:

- [American Roulette: international operator description, zero pockets and five-number wager](https://www.pokerstars.com/casino/game/american-roulette/3200/11/) — PokerStars. Checked 2026-10-29.
- [House edge across casino games: La Partage on qualifying even-money bets](https://www.pokerstars.com/casino/news/understanding-house-edge-across-different-casino-games/6205/) — PokerStars Casino Blog. Checked 2026-10-29.

## What should you check at a GB roulette table?

1. Identify the actual pocket labels and number of pockets, rather than relying on the lobby title.
2. Read the payout units: profit odds or total return, including the treatment of the winning stake.
3. Check what happens on zero for each wager and whether a special rule applies.
4. Add all selected wagers and any feature cost to establish the total committed per round.
5. Read the exact published return information for modified games rather than importing the standard figures.
6. Check the licensed GB operator and use its round history and verified support route if a settlement is unclear.

Live presentation and a computer-generated presentation can use the same conventional payout model, but a camera does not establish the rules. Our [live-casino guide](https://howtocasino.uk/guides/what-is-live-casino/index.md) explains the supplier, operator and streamed-game distinction; the [licence-checking guide](https://howtocasino.uk/guides/how-to-check-casino-licence/index.md) covers the GB domain and permission checks.

Sources:

- [RTS 3: rules, game descriptions and likelihood of winning](https://www.gamblingcommission.gov.uk/manual/remote-gambling-and-software-technical-standards/rts-3-rules-game-descriptions-and-the-likelihood-of-winning) — Gambling Commission. Checked 2026-10-29.

## Related questions

### What is single-zero roulette?

The conventional version has thirty-seven pockets: numbers 1–36 and one 0. It is often called European roulette. Check payouts and zero rules separately; a single zero alone does not establish the house edge of a modified game.

### Is double zero the same number as zero?

No. On the conventional double-zero wheel, 0 and 00 are separate pockets. A straight-up wager on one does not win when the other lands.

### Why is single-zero roulette usually a lower-edge game?

With the same conventional payouts, it has one fewer losing outcome. A straight-up £1 bet paying 35:1 profit has an expected loss of 1/37 on single zero versus 2/38 on double zero, about 2.70% versus 5.26%.

### Is red a 50/50 bet?

Not on either conventional wheel. Eighteen red pockets out of thirty-seven give about 48.65%; eighteen out of thirty-eight give about 47.37%. Zero pockets are outside red/black.

### Does 35:1 return £35 or £36 from a winning £1 stake?

When 35:1 is the profit payout and the winning stake is returned, the total is £36: £35 winnings plus the original £1. Read the exact game's definition of any displayed multiplier.

### Does La Partage apply to every roulette bet?

No. The half-stake zero return concerns the qualifying even-money bets specified by that table. It does not automatically apply to numbers, dozens or columns, and it does not increase the probability of red or black landing.

## Sources and checks

- [European Roulette: international operator description and conventional payout table](https://www.pokerstars.com/casino/game/gdk-roulette-european/3200/1/) — PokerStars. Checked 2026-10-29.
- [American Roulette: international operator description, zero pockets and five-number wager](https://www.pokerstars.com/casino/game/american-roulette/3200/11/) — PokerStars. Checked 2026-10-29.
- [House edge across casino games: La Partage on qualifying even-money bets](https://www.pokerstars.com/casino/news/understanding-house-edge-across-different-casino-games/6205/) — PokerStars Casino Blog. Checked 2026-10-29.
- [RTS 3: rules, game descriptions and likelihood of winning](https://www.gamblingcommission.gov.uk/manual/remote-gambling-and-software-technical-standards/rts-3-rules-game-descriptions-and-the-likelihood-of-winning) — Gambling Commission. Checked 2026-10-29.

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- [How do you check if an online casino is legitimate in the UK?](https://howtocasino.uk/guides/how-to-check-casino-licence/index.md)

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