House Edge Calculator
Every Wager Reduces to One Number
Whatever the game, a bet's house edge collapses into a single expected value calculation: what you're statistically expected to lose per unit wagered, averaged over a large number of plays. This calculator computes that figure directly from any win probability and payout structure, so you can evaluate a wager that doesn't fall into one of the standard named games.
The Formula
EV (per unit bet) = (P(win) × Payout) − (P(lose) × 1)
House Edge = −EV × 100
House Edge = −EV × 100
Payout is expressed as "to one" — a payout of 1 means an even-money bet (win $1 for every $1 wagered), while a payout of 35 means a 35:1 payout, as on a straight-up roulette number.
Where This Gets Used
- Evaluating an unfamiliar side bet — casino table games often add optional side bets with nonstandard payouts; this calculates the exact edge from the stated odds.
- Comparing games mathematically — house edge is the single number that lets you compare a roulette bet, a slot machine, and a sports wager on the same scale.
- Teaching expected value — a direct, numeric example of how probability and payout combine into a single statistical expectation.
How to Use This Calculator
- Enter Win Probability as a percentage.
- Enter Payout, expressed as "to one" (e.g. enter 1 for an even-money bet, 35 for a 35:1 payout).
- Select Calculate to see the house edge as a percentage.
Related Calculations
Apply this same formula to a specific roulette bet with the Roulette Odds Calculator, or check a slot machine's expected loss with the Slot Machine RTP Calculator.