Lottery Odds Calculator

About this calculator

This calculator uses the combinations formula (n choose k, written C(n,k) = n!/(k!(n-k)!)) to work out how many possible number combinations exist in a lottery, and inverts that figure to give the odds of any single ticket matching the winning numbers. It accounts for whether a bonus/power ball is drawn from a separate pool, which multiplies the total combinations and long odds even further.

It's used by lottery players comparing the odds of different games (a 6/49 draw versus a 5/70 game with a separate power ball, for example), and by anyone wanting to understand, in concrete terms, just how unlikely a jackpot win actually is — often expressed as 1 in tens or hundreds of millions.