Free tools
Betting calculators
The arithmetic behind every price and every stake, done in your browser. The same sums the site runs on every fixture, for numbers of your own.
Odds converter
Decimal, fractional and American odds side by side, with the probability each implies.
Open →Implied probability calculator
What a price says about the chance of an outcome, and the fair price for a probability.
Open →Bookmaker margin calculator
The overround built into a market, and the fair odds once it is removed.
Open →Expected value calculator
Whether a price beats your probability, and by how much per unit staked.
Open →Kelly criterion calculator
A stake sized to the edge, with the fraction and cap we use ourselves.
Open →Accumulator calculator
Combined odds, returns and the true chance of an accumulator landing.
Open →Poisson football calculator
Expected goals in, match result, totals, both teams to score and likely scores out.
Open →
Why these tools
Every one of them answers a question a reader asks on the way to a bet: what does this price mean, how much is the bookmaker keeping, is the price better than my own estimate, how much should I stake, and what does a goal expectation say about the score. They are the same calculations this site publishes for every fixture — the model against the market, the fair prices on every match page and the quarter-Kelly stakes on every advised bet — opened up so you can run them on numbers of your own.
None of them stores anything, none needs an account, and none tells you whether your probability is right. That last part is the whole difficulty of betting, and how we approach it is written up in full.