Roulette on Duel.com: Bets, Odds and House Edge

Standard roulette is the simplest casino game to price. Every bet pays as if the wheel had 36 pockets, and the wheel has 37 or 38. The difference is the house edge, and it is the same for almost every bet on the layout.

On Duel.com you need to know which kind of roulette you have opened, because the two are different games with different maths.

Roulette on Duel.com: two different products#

Castle Roulette: the 48-step multiplier wheel#

Castle Roulette is not a 37-pocket wheel with red, black and numbers. Each round produces a roll from 0 to 47, every roll equally likely, and the roll decides which multiplier the wheel lands on.

The roll is not tied to a fixed position on the wheel. Two rounds with the same roll can stop on different segments that carry the same multiplier.

What the table says about the edge#

The last column is the arithmetic that matters. Each multiplier times its probability equals exactly 1: 2x half the time, 4x a quarter of the time, 48x once in 48. Read as a bet on a multiplier that pays that multiple of your stake when the wheel lands on it, every line returns exactly your stake on average. By the published table, each bet is fair before any edge adjustment.

Duel prices its Originals under the Zero Edge model: a 0.1% base house edge, refunded as instant rakeback while you are inside the daily allowance of $50,000 wagered with a $1,000 per-bet cap, resetting at 00:00 UTC. The table above contains no 0.1%. How that base edge is applied in Castle Roulette is not documented, so we do not state a house edge for this game beyond the table. The multipliers and rules shown in the game are what apply to your bet; read them, along with the maximum bet and maximum win, before you stake anything.

What the table does tell you is the shape of each bet. All six have the same expected return and very different swings: 2x wins every second round on average, 48x loses 47 rounds in 48.

How a Castle Roulette roll is generated#

Castle Roulette is a shared round, so it does not use your personal client seed. Like Duel Crash, it uses a value from drand, a public, distributed randomness beacon whose values nobody, including Duel, can predict or choose.

Before the round, Duel shows the SHA-256 hash of the round's server seed and a drand round ID that points to a value not yet published. Once drand publishes it, the roll is derived as follows:

message = drand value for that round, followed by :0   (the nonce is always 0)
value   = first 4 bytes of HMAC-SHA256(key = server seed, message), read as a number
roll    = value mod 48

In Duel's published example the value is 2,476,785,275. Divided into groups of 48 it leaves 11, and a roll of 11 pays 8x.

Duel committed to its seed and to the round ID before the drand value existed, so it cannot steer the roll, and players cannot compute it early because the server seed is hidden until afterwards. One footnote for the exact-minded: 2^32 is not a multiple of 48, and Duel documents no rejection range for this game. If none is applied, rolls 0 to 15 are each more likely than the rest by about one part in 89 million, which is far too small to matter.

To check a round, use Duel's verifier at duel.com/fairness/verify or the script in how to verify a bet. The drand value comes from drand's own public API at api.drand.sh/v2/beacons/quicknet/rounds/ followed by the round ID, not from Duel.

Everything from here on describes standard roulette, which is what the provider and live tables use.

The wheels#

La partage returns half of an even-money stake when the ball lands on zero, which halves the edge on those bets. Whether a given table offers it is shown in that table's rules.

Bet types and payouts#

Payouts are identical on single-zero and double-zero wheels. Only the probability changes.

Where the edge comes from#

Take a straight-up bet of 1 unit on a European wheel. You win 35 units once in 37 spins and lose 1 unit the other 36 times:

(1/37 × 35) − (36/37 × 1) = −1/37 = −2.70%

Now red or black. You win 1 unit 18 times in 37 and lose 1 unit 19 times:

(18/37 × 1) − (19/37 × 1) = −1/37 = −2.70%

The result is the same for every bet in the table, because each one pays as though there were 36 pockets. On an American wheel the same sums give −2/38, or −5.26%. The one exception is the five-number bet, which pays 6 to 1 on five numbers and works out at −7.89%, the worst bet on either wheel.

Expected loss follows total wagered, not your deposit. Fifty spins at 20 units is 1,000 wagered even if you only brought 200. Actual results over a session will sit well above or below these averages; see house edge and RTP explained.

If a provider lobby offers both wheels, the single-zero wheel costs about half as much to play. No reason exists to choose double zero when both are available.

Inside and outside bets: same edge, different ride#

Covering more of the layout does not help either. Red plus a dozen plus a few numbers is several bets, each paying the same edge on its own stake. Covering 36 of 37 numbers wins almost every spin and still loses 2.70% of the total staked on average.

Why betting systems do not change expected value#

Each spin is independent. After ten reds in a row, the chance of red on a European wheel is still 18 in 37. The history board shows what happened; it carries no information about what comes next.

A betting system decides how much to stake and when. It cannot change the expected value of a bet, because every bet on the wheel has the same negative expectation and a sum of negative numbers is negative. What a system does change is the shape of your results.

Martingale, doubling after each loss on an even-money bet, shows this clearly. Starting at 1 unit and allowing ten doublings:

Many small wins, and one loss that takes them all back with interest. The expected loss is still exactly the house edge times the amount wagered. Table maximums and a finite bankroll are what make the long streak fatal, and both always exist.

• Martingale: small frequent wins, rare ruinous loss, same edge
• Fibonacci and D'Alembert: slower progressions, same edge
• Betting on 'due' numbers or colours: spins are independent
• Hot and cold sectors: an RNG or a balanced wheel has no memory
• Covering most of the table: you pay the edge on every chip placed

The same logic holds on a zero-edge game. With no house edge the expected value of every bet is zero, and a progression still cannot make it positive. Duel's zero-edge allowance also caps bets at $1,000, so a doubling sequence leaves the zero-edge range quickly.

Playing a session sensibly#

To check a Castle Roulette round, follow how to verify a bet. For how the refund on Originals and the rakeback on provider games are credited, see rakeback explained.

Summary#

Standard roulette has a 2.70% edge on a single-zero wheel and 5.26% on a double-zero wheel, on every bet except the American five-number bet at 7.89%. Third-party and live tables on Duel.com run at those provider edges. Castle Roulette is a different game: a provably fair Duel Original with 48 equally likely rolls paying 2x to 48x, where each multiplier times its probability equals exactly 1. How the Originals' 0.1% base edge applies to it is not documented. Bet selection changes variance, not cost, and no staking system changes expected value.