Free Roulette Payout Calculator

Roulette Odds Calculator – Plan Your Betting Strategy

A Roulette Payout Calculator (often called a Roulette Odds Calculator or Roulette Probability Calculator) helps you evaluate different betting scenarios by computing the probability of winning and the net profit for any wager amount. Whether you are playing European or American roulette, this tool allows you to estimate potential returns and compare payouts across bet types. By understanding the numbers behind the wheel, you can make more informed betting decisions.

How Roulette Is Played

In a standard game of roulette, the dealer spins the wheel in one direction and releases a small ball in the opposite direction. Players place chips on a betting layout, predicting where the ball will come to rest. If the prediction is correct, the player receives back the original stake plus a payout that depends on the type of bet placed. The payout is calculated from the number of spaces the bet covers, making it possible to compare risk and reward before the wheel stops.

European vs. American Roulette Layout

The roulette wheel contains numbers from 0 to 36, alternately colored black and red, with zero (0) marked in green. There are two main versions of the game:

• European roulette: features a single zero (0) and a total of 37 slots.
• American roulette: includes an additional double zero (00), bringing the total to 38 slots.

The extra green pocket in American roulette increases the house advantage. Although the difference may seem small, it significantly affects the long‑run expected value for players.

Calculating Roulette Odds Step by Step

To find the probability of a given bet:

1. Count the number of winning scenarios (spaces that would make the bet win).
2. Divide that count by the total number of possible outcomes (37 for European, 38 for American).
3. Multiply the result by 100 to convert it into a percentage.

For example, betting on a single number (straight) has 1 winning scenario. The probability is $\dfrac{1}{37} \approx 2.70\%$ in European roulette and $\dfrac{1}{38} \approx 2.63\%$ in American roulette.

Types of Bets and Their Payouts

Roulette bets are divided into two categories: outside bets (placed on the edges of the layout) and inside bets (placed on specific numbers or small groups). The payout for any bet follows the formula:

$$\text{Payout ratio} = \dfrac{36}{S} - 1$$

where $S$ is the number of spaces the bet covers. The result is expressed as “X to 1”, meaning you win X times your stake in addition to getting the original bet back.

The table below summarizes the most common bets, their coverage, probabilities, and payouts.

Bet Type	Coverage (spaces)	European Odds	American Odds	Payout
Straight	1	2.70%	2.63%	35:1
Split	2	5.41%	5.26%	17:1
Street	3	8.11%	7.90%	11:1
Corner	4	10.81%	10.53%	8:1
Double Street	6	16.22%	15.79%	5:1
Red/Black	18	48.65%	47.37%	1:1
Even/Odd	18	48.65%	47.37%	1:1
1‑18 / 19‑36	18	48.65%	47.37%	1:1
Dozens (1‑12, 13‑24, 25‑36)	12	32.43%	31.58%	2:1
Column	12	32.43%	31.58%	2:1

For outside bets like Red/Black and Even/Odd, the odds are close to 50% but are not exactly even because the green zero(s) tilt the balance in favor of the house.

Understanding House Edge in Roulette

The house edge (or expected value) represents the average loss a player can expect per bet in the long run. It is calculated using the general formula:

$$\text{EV} = P(\text{win}) \times (\text{net win}) - P(\text{lose}) \times (\text{net loss})$$

For any $1 bet in European roulette:

$$\text{EV} = \frac{1}{37} \times 35 + \frac{36}{37} \times (-1) = -\frac{1}{37} \approx -0.0270$$

This means the house edge is $2.70\%$. In American roulette, due to the extra zero, the calculation becomes:

$$\text{EV} = \frac{1}{38} \times 35 + \frac{37}{38} \times (-1) = -\frac{2}{38} \approx -0.0526$$

giving a house edge of $5.26\%$. These values are constant for nearly all bet types because the payout structure is balanced against the odds. The green pockets are the primary reason casinos maintain a mathematical advantage over time.

Why Use a Roulette Payout Calculator?

A dedicated roulette odds calculator removes the need for manual arithmetic. By selecting your bet type, the version of roulette, and your stake, the tool instantly shows the probability of winning, the exact payout ratio, and the net profit if the bet succeeds. It also highlights the difference in house edge between European and American tables, helping you choose the game with the lower casino advantage. Whether you are a casual player or building a betting strategy, this calculator serves as a quick reference for understanding risk and reward.