Single-bet only
American odds

Calculator

Use EV if you have an opinion on win probability. Use implied probability if you just want break-even math.

Enter inputs

American odds e.g. -110 or +150

Stake $

Your win probability %

Display format

Tip: if you don’t have a real win % estimate, EV output is meaningless. Use implied probability first.

Betting math guides

Short explanations that match what this calculator is doing under the hood.

What this calculator does

BettorCalc is a sports betting EV calculator and implied probability (break-even) tool for American odds. It answers two different questions:

Reality check: EV is only as good as your win-probability estimate. If you don’t have a reason for your % (model, matchup analysis, market comparison), use implied probability as your baseline.

Quick definitions

Implied probability (break-even)

Implied probability is the win rate required to break even at the listed odds. For example, -110 implies about 52.38% break-even. That’s not a prediction—it’s the price translated into a percentage.

Expected value (EV)

EV is the long-run average profit or loss per bet. This calculator uses: EV = p(win) × profit − (1 − p(win)) × stake. A positive EV means you expect to make money over many bets if your probability estimate is accurate.

Next reading

If you want this to be more than guessing, read these (they’re short):

Use the calculator Learn EV