Methodology
Every number on this site is computed by one program and checked by a second, independent method before the site can be built. If the two disagree, nothing is published.
Odds, margins and parlays
Exact fractions: every conversion is checked by converting back, every margin by computing the expected value of each outcome at fair probabilities, and parlay prices by the product of their legs. Parlay hit rates and returns are also checked by simulating 400,000 four-leg and six-leg parlays.
Kelly staking
The Kelly fraction and the expected log growth come from their closed forms; the growth is checked by simulating 4,000 bankrolls over 1,000 bets each, and the fraction by checking that stakes around it grow more slowly.
Hedges, arbitrage, each-way and lay bets
Every outcome is settled by hand in the program: a hedge or a lay stake is accepted only if the results of both outcomes are equal, and an arbitrage only if every outcome returns the same amount.
What we do not claim
Our figures describe prices, not predictions. We give no tips, and no calculator on this site turns a bet with a negative expected value into a profitable one.
Updated: