Roulette
Green, zero and double-zero odds
One chosen zero is one pocket. Any green means one, two or three pockets depending on the wheel. That distinction changes the probability and the required bets.
5.26%
Any green on an American wheel
2 / 38 • 0 and 00 are separate pockets
One specific zero
A straight-up on 0 has a 1/37 chance on European roulette, 1/38 on American roulette and 1/39 on triple zero. A straight-up on 00 is a separate ticket and is only available when that pocket exists.
The chance of any green
Any green occurs with probability 1/37, 2/38 or 3/39 on the three wheel types. That is 2.70%, 5.26% and 7.69%. These are event probabilities, not the payout for a universal green button.
Green does not automatically pay more
A standard straight-up zero pays 35:1, just like another single number. Covering both 0 and 00 with two equal straight-up bets doubles the total stake. If either wins, one ticket wins and the other loses.
Two zero bets on an American wheel
Place a hypothetical $1 on 0 and $1 on 00. Either zero returns $36 total, for $34 net profit after both stakes. Any other number loses $2. The chance of positive profit is 2/38, or 5.26%.