Odds converter & calculators
Every box accepts decimal (2.50), fractional (3/2) or American (+150, −200) odds. Results update as you type.
Odds converter
See any price in all three formats, with the probability it implies.
Bookmaker margin calculator
Enter every outcome of one market (two for a moneyline, three for a football match result). Leave the third box empty for a two-way market.
Fair odds without the margin
Accumulator (parlay) calculator
Add up to 20 selections. Every selection must win for the bet to pay.
Frequently asked questions
How do I convert American odds to decimal?
For positive American odds, divide by 100 and add 1: +150 becomes 2.50. For negative odds, divide 100 by the number without its minus sign and add 1: −200 becomes 1.50.
What is a good bookmaker margin?
On a two-way market such as a moneyline, around 4% to 5% is typical and under 3% is sharp. Three-way football markets usually carry 5% to 8%. The lower the margin, the closer the prices are to fair odds.
How are accumulator odds calculated?
Multiply the decimal odds of every selection. Three selections at 2.00, 1.80 and 1.50 give 5.40, so a 10-unit stake returns 54 units if all three win. One losing selection loses the whole bet.