Roulette Calculator

How this roulette calculator works

The calculator first loads the selected layout: 37 outcomes for a single-zero wheel or 38 for the double-zero version.

It measures how much of that layout the chosen bet covers and applies the published winning ratio. For the coverage and table position behind each standard wager, see the roulette bet types and placement guide. When several positions overlap on the same spin, use the combined-bet outcome calculator instead of adding the results manually.

Win probability is kept separate from money returned on a winning spin. For exact one-spin and repeated-spin hit calculations, use the repeated-spin probability tool. For gross return, net profit and reverse target-stake calculations, use the stake and return calculator.

Expected loss is not a prediction for the next spin. It is the long-term mathematical cost of the selected stake size, wheel type and number of spins. The RTP and house-edge calculator isolates that long-run percentage cost, while the roulette session simulator compares random session paths with theoretical results.

How wheel rules change the estimate

European roulette has one zero, so the standard house edge is 1 divided by 37, or about 2.70%. American roulette adds a double zero, raising the base house edge to 2 divided by 38, or about 5.26%. The roulette wheel layout guide maps those pocket counts, zero formats and number order.

French roulette usually uses the same single-zero wheel as European roulette, but rules such as la partage can reduce the cost of even-money bets when zero lands. That reduced edge does not apply to inside bets like straight, split or corner. The wheel and zero-settlement rules explain how these outcomes are handled at the table.

With the same standard bet and payout, a single-zero wheel has a lower expected cost than a double-zero wheel. Zero is a winning outcome when your bet covers it; it is not always a losing pocket. Compare actual table formats and rules at https://roulettecalc.com/casinos/.

Read each result as a different measure

Win probability describes how much of the wheel the selected bet covers. Across repeated spins, the chance of at least one hit rises, but the probability of any individual spin does not change because previous results do not alter the wheel.

Gross return includes the original stake returned after a win. Net profit excludes that returned stake, so a $10 straight bet that wins at 35:1 shows $350 net profit and $360 gross return.

Expected loss is a long-run average based on total stake and house edge, not a forecast for the current session. A short session can finish above or below that average because actual results vary around the mathematical expectation.

A hit is not the same as a profitable session. If a $10 straight bet hits once in 40 spins and misses the other 39, its $360 gross return is less than the $400 wagered: the session finishes $40 down. The at-least-one-hit result does not calculate your chance of finishing ahead.

Total wagered is turnover, not starting bankroll. The estimate assumes you place the same stake on every selected spin, with independent, equally likely pocket outcomes. It does not stop early for a depleted bankroll, a profit target or a table limit.

What the calculator cannot do

The tool cannot predict the next number, color or section of the wheel. Each spin is treated as an independent event, and previous spins do not make a number due.

Betting systems such as Martingale or Fibonacci can change how quickly a bankroll rises or falls, but they do not remove the house edge built into the wheel. The bankroll-risk and betting-system guide compares those progressions without treating them as a way to beat roulette.

Use the results as a risk and payout estimate, not as a signal for choosing the next number. The spin-history analysis tool explains what observed frequencies can tell you; the fairness and settlement checks separate a surprising sequence from evidence about a game or payment.