Roulette: inside or outside bets, what are the differences?

On a European roulette table, the boundary between “inside bets” and “outside bets” is directly visible on the layout. Inside bets are placed in the numbered area from 0 to 36 and cover a small number of pockets. Outside bets are located around the number grid and cover large groups: red/black, even/odd, low/high, dozens and columns.

The difference is not merely a matter of vocabulary. It changes how often a bet can win, the payout received when it wins and the volatility felt during a session. However, on a standard European roulette wheel, many of these bets share the same mathematical house edge. Betting “wider” therefore does not remove the zero.

Start by reading the roulette layout

A European roulette wheel has 37 numbers: 0 and 1 to 36. On the layout, numbers 1 to 36 form a grid of three columns. The zero is located at the end of this grid.

Inside the numbered area, the exact position of the chip determines how many numbers are covered. A chip in the centre of a number is a straight-up bet. A chip on the line separating two numbers is a split. At the intersection of four numbers, it becomes a corner. This geography is the basis of inside bets.

Outside, the boxes are already labelled: red, black, even, odd, 1-18, 19-36, first dozen, second dozen, third dozen and the three columns. The player therefore does not have to construct the combination: they choose a predefined group.

Inside bets: fewer numbers, higher payouts

Straight-up: one number

A straight-up bet covers one number. On a European roulette wheel, the probability of hitting that number on the next spin is 1 in 37, or about 2.70%. The standard payout is 35 to 1: a winning bet earns 35 units of profit, plus the return of the original stake.

Split: two neighbouring numbers

A split covers two adjacent numbers on the layout. Its probability is 2 in 37, or about 5.41%, and the standard payout is 17 to 1.

Street: three numbers

A street covers a horizontal row of three numbers, for example 7-8-9. The probability is 3 in 37, or about 8.11%, for a standard payout of 11 to 1.

Corner: four numbers

The chip is placed at the intersection of four boxes. A corner therefore covers four numbers and generally pays 8 to 1. Its probability of winning on the next spin is 4 in 37, about 10.81%.

Six line: six numbers

A six-line bet covers two consecutive rows of three numbers. It wins on 6 numbers out of 37 and normally pays 5 to 1.

Outside bets: cover more numbers for a lower payout

Red/black, even/odd, low/high

These even-money bets cover 18 numbers. Red does not cover zero; neither does black. Even and odd also exclude zero, as do 1-18 and 19-36. The probability of winning is therefore 18 in 37, or about 48.65%, not 50%.

The standard payout is 1 to 1. A winning €10 bet produces €10 profit, plus the return of the €10 staked.

Dozens

Each dozen covers 12 numbers: 1-12, 13-24 or 25-36. The probability is 12 in 37, about 32.43%, and the standard payout is 2 to 1.

Columns

Each column on the layout contains 12 numbers. Mathematically, a standard column therefore works like a dozen: 12 numbers covered and a payout of 2 to 1.

Inside or outside bets: which one “wins more often”?

If we are talking only about frequency on a single spin, an even-money bet wins more often than a straight-up bet: 18 numbers versus 1. But it pays much less. This is the central trade-off in roulette.

Comparing only the percentage of winning spins can therefore be misleading. An inside bet can lose many spins and then produce a large payout. An outside bet can alternate wins and losses more often, but each win is smaller. Both profiles can result in the same mathematical house edge on a standard European roulette wheel.

Why the house edge often remains the same

Take a €1 straight-up bet. You win with a probability of 1/37 and then make €35 profit; you lose €1 in the other 36 cases. The expected value is therefore: (1/37 x 35) - (36/37 x 1), or about -€0.027. This corresponds to a house edge of about 2.70%.

Now take €1 on red. You win €1 profit on 18 numbers and lose €1 on the other 19 outcomes, including zero. The expected value is: (18/37 x 1) - (19/37 x 1), again about -€0.027.

The frequency changes, the payout changes, but the presence of zero maintains the same mathematical imbalance on these standard bets.

Example: €12 distributed in three different ways

Option A: €12 on red. A single bet covers 18 numbers. If red comes up, the profit is €12. If black or zero comes up, the stake is lost.

Option B: €1 on twelve different straight-up numbers. You cover fewer numbers, but if one of them comes up, the winning straight-up bet pays 35 to 1 while the other eleven bets are lost. The net result is then very different from a simple dozen, even though twelve numbers have been covered.

Option C: €12 on a dozen. You also cover twelve numbers, but the payout is 2 to 1 on the entire stake. The result profile is simpler and less dispersed than twelve separate straight-up bets.

This example shows that “number of covered numbers” is not enough to compare two betting strategies. You also need to look at how the bankroll is distributed and how each combination is paid.

Can inside and outside bets be combined?

Yes. Nothing requires you to choose a single family. A player can, for example, place an outside bet on a dozen and a few straight-up bets on specific numbers. The problem is that each added chip increases the total stake for the spin.

Before looking for sophisticated coverage, calculate the full stake. Five €1 chips on straight-up numbers and €10 on red represent €15 committed, not “a €10 bet with a few extra numbers”. This confusion is common when the interface displays many chips at the same time.

Are outside bets “safer”?

They win more frequently, but “safer” is too strong a term. Red can lose ten times in a row; a rare streak remains possible. In addition, zero causes even-money bets to lose on a standard European roulette wheel, except under special rules such as La Partage or En Prison on certain French roulette tables.

A higher winning frequency generally reduces the size of some short-term swings, but it does not turn roulette into a risk-free game.

Are inside bets reserved for experienced players?

No. They are mainly more precise to place. Straight-up, split and corner bets require an understanding of the layout’s geography. Once that reading is acquired, the rules are simple.

Experience matters more in managing the total stake. A player can easily multiply small chips inside the table and end up committing much more than they think. A good habit is to check the total displayed value before confirming the spin.

How to choose according to the way you play

If you prefer more frequent results with modest payouts, even-money bets are the easiest to understand. If you accept more losing spins in exchange for higher individual payouts, inside bets fit that profile more closely.

Dozens and columns form a middle ground: they cover 12 numbers and pay 2 to 1. They are useful for understanding how roulette allows you to adjust the width of your coverage without moving directly from a straight-up bet to an even-money bet.

FAQ - Inside and outside roulette bets

Which bet covers the most numbers?

Among standard simple bets, red/black, even/odd and 1-18/19-36 cover 18 numbers out of 37.

Which bet pays the most?

A standard straight-up bet pays 35 to 1 because it covers only one number.

Is a dozen the same as twelve straight-up numbers?

No. Both can cover twelve numbers, but the distribution of the stake and the payout are not the same.

Is zero red or black?

No. Zero is green and causes red/black, even/odd and low/high bets to lose on standard European roulette.

Do outside bets have a better RTP?

On a standard European roulette wheel without a special rule, most classic bets have the same house edge of about 2.70%. What mainly changes is the frequency and size of the wins.