The roulette odds calculator translates a wheel selection into a probability and a long-run average. Enter a wheel type, a supported bet, and a virtual stake. Its result separates the chance of winning from the amount earned on a win, helping you avoid confusing payout ratios with probabilities.
Check your understanding
A single pocket on a 37-pocket wheel has probability 1/37. After ten misses, what changes?
Read the explanation
Independent spins have the same probability. Previous misses do not change the wheel model.
Your learning exercise
Compare one covered pocket on 37 and 38 pockets. Keep the net payout the same and inspect expected value.
Before using the demonstration, answer the concept question above. Afterwards, explain the result using the assumptions on this page.
Roulette odds calculator inputs
Select European for 37 pockets or American for 38. A straight-up selection covers one pocket, while the supported red and even groups each cover eighteen. The ordinary payout is 35 to one for a single number and one to one for the outside selections. The model excludes special zero treatments. The pocket input identifies a numbered straight-up choice; American double zero has the same probability and payout as any other individual American pocket.
Compare the same selection on two wheels
For an even selection, the European winning probability is eighteen divided by 37, about 48.65 percent. The American equivalent is eighteen divided by 38, about 47.37 percent. The odds fall because the added pocket loses the selection. The award for a win does not change. A 24-credit European even selection either gains 24 credits or loses 24 credits in one spin. Its expected net change is minus 24 divided by 37, approximately minus 0.649 credits.
Calculate expectation from both outcomes
Expected net change combines the winning net amount times its probability and the losing net amount times its probability. For one unit on an American individual pocket, the expression is 35 times one divided by 38, minus 37 divided by 38. This simplifies to minus two divided by 38. Its negative value corresponds to a house edge of about 5.26 percent. The displayed percentage concerns the stated standard rules, rather than a forecast of the next sampled pocket.
Use the result within its assumptions
Changing the stake scales the credit amount without changing the underlying probability. Changing the wheel changes the denominator. Selecting another ordinary straight-up pocket changes its label without changing its likelihood under uniform sampling. These relationships explain the form more reliably than a betting sequence. The calculator does not cover every roulette layout or a table with special zero refunds. Check the rules before transferring a number to another setting, and avoid treating a long-run average as a guaranteed session balance.
Common questions
Does a higher stake improve the probability?
No. It changes the amount at risk and the corresponding payout only.
Can the calculator predict a pocket?
No. It reports probabilities under a specified uniform wheel model.