Odds Converter is a quick, simple tool to convert fractional, decimal and moneyline Guide to UK, American and European odds formats and betting calculators. Bet calculator at Oddschecker helps you work out odds and winnings for multiple bets. Combine the bets to calculate the acca and permutation betting totals. How to Calculate Odds. The mathematical concept of odds is related to, yet distinct from the concept of What are the better odds in horse racing: 3/1 or 5/2?.