Betting calculators

Free, instant, no account. Every calculator runs the same math as WeBall's grading engine, and every result is linkable — change the inputs and the address bar updates so you can share exactly what you're looking at.

13 calculators

Convert

Move between odds formats and probability.

Odds ConverterConvert American, decimal and fractional odds into each other and into implied probability, instantly and in both directions.Implied Probability CalculatorTurn any betting odds into the probability they imply, and turn a probability back into the odds that would price it fairly.

Price

Work out what a market really costs you.

No-Vig Fair Odds CalculatorStrip the bookmaker's margin out of a two-way or three-way market to see what the market really thinks before it takes its cut.Hold CalculatorWork out exactly how much a sportsbook is keeping on any market, from a standard spread to a wide-margin player prop.Parlay CalculatorAdd up any number of legs to see the combined odds and payout, plus the fair price the parlay should pay without the vig.

Value

Decide whether a bet is worth making.

Expected Value CalculatorCalculate the expected value of a bet from your win probability and the price on offer, in both percentage and dollar terms.Breakeven Win Rate CalculatorFind the win percentage a bet needs just to break even at a given price — the bar every wager has to clear before it profits.Closing Line Value CalculatorCompare the price you got against the closing line to see whether you beat the market — the best early signal that a process works.Arbitrage CalculatorCheck whether two prices at different books guarantee a profit, and split your stake to lock the same return either way.

Stake

Decide how much to put on it.

Kelly Criterion CalculatorWork out the mathematically optimal stake for a given edge, with fractional Kelly options because full Kelly is far too aggressive.Hedge CalculatorFind the stake on the other side that locks in a guaranteed profit, and see exactly what you keep either way.

Promos

Check whether a promotion is actually worth taking.

Odds Boost EV CalculatorDecide whether a profit boost is actually worth taking by comparing the boosted price against the market's fair probability.Free Bet Conversion CalculatorWork out what a free bet is really worth in cash, since the stake is not returned and long shots convert at a higher rate.