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Odds to Probability Calculator

Convert odds in favor (a : b) into a probability percentage.

Probability
75%

Formula: P = a / (a + b) × 100

About Odds to Probability Calculator

Odds to Probability Calculator is a free online calculator that gives you an instant, accurate result as you type. Convert odds in favor (a : b) into a probability percentage.

The calculation uses the standard formula P = a / (a + b) × 100 and updates live with every change to the inputs. Everything runs client-side in your browser — fast, private, and free to use as often as you like.

Odds of 1:1 ("even odds") correspond to a 50% probability, while 3:1 odds in favor mean a 75% chance.

Frequently Asked Questions

Is Odds to Probability Calculator free to use?

Yes. Odds to Probability Calculator is completely free, with no sign-up, no downloads, and no usage limits. You can use it as many times as you like on any device with a web browser.

How accurate is this calculator?

The calculator applies the standard formula (P = a / (a + b) × 100) with full floating-point precision and rounds only the displayed result. For most practical purposes the results are exact.