About Fair Odds Calculator
Fair Odds Calculator publishes one thing: the arithmetic for reading odds. Converting an American price to the probability it implies, taking a bookmaker's margin out of a two-sided market to leave the fair price, measuring an edge against a price, and multiplying legs into one number. Every calculator runs in the browser on figures the reader types, shows every step, and is free without an account.
Why this site exists
Because the arithmetic that turns a price into a probability is short, checkable and almost always missing from the places that quote prices, and because every free version of it sits on a page whose purpose is to take a deposit. Publishing it on its own, with no price attached and nobody paid either way, is a small thing nobody had done plainly.
Who it is for
Adults in the United States who already have a price in front of them and want to know what it says: somebody comparing two markets on the same event, somebody testing a model against a posted number, and anybody who would rather see a conversion written out than have it done invisibly.
What it does not do
- No tips, picks, selections or predictions. This site does not say what will happen or what anybody should do, on any market.
- No odds of its own. The site holds no prices and no feed; every figure on every page comes from what the reader typed in.
- No operator links and no operator money. No sportsbook, exchange or prediction venue is named, linked, ranked or paid to appear, and none pays this site.
- No profit claims. Nothing here suggests that a positive expected value, an arbitrage or any other arithmetic produces income.
What is on this site
3 free calculators, each working its figure on the page with no account and nothing to buy. All calculators.
- Expected Value Calculator: A price and your probability in, the break-even, the edge in points and the expected value out
- No Vig Calculator and No Vig Odds Calculator: Both sides of a market in, the overround, the hold and the fair vig-free price out
- Parlay Calculator Odds and Payout: Two to four legs in, one decimal and American price out, with the probability it implies
Who answers for it
Joseph Ellul, Operator, Ellul MT. Responsible for the arithmetic published here and for correcting it. A correction that names the page and the figure is acted on.
Reach us
Contact for a question about anything here, or hello@fairoddscalculator.com. The legal terms are on Terms and Privacy.