Betting Odds Converter

The three odds formats

Bookmakers express the same price in different ways depending on where you are:

• Decimal (e.g. 2.50): common in Europe, Australia and New Zealand. The total returned per 1 unit staked, including your stake.
• Fractional (e.g. 6/4): traditional in the UK and Ireland. Profit relative to stake: win 6 for every 4 staked.
• American (e.g. +150 / −200): used in the US. A plus number is the profit on a 100 stake; a minus number is how much you must stake to win 100.

How the conversion works

Everything goes through decimal odds:

• Fractional a/b → decimal = a ÷ b + 1
• American +X → decimal = X ÷ 100 + 1
• American −X → decimal = 100 ÷ X + 1

The implied probability is 1 ÷ decimal odds × 100%: the chance the price suggests, before removing the bookmaker's margin.

Worked example

6/4 = 1.5 + 1 = 2.50 decimal = +150 American. Implied probability: 1 ÷ 2.5 = 40%. A 10 stake returns 25 (15 profit plus the 10 stake).

−200 American = 100 ÷ 200 + 1 = 1.50 decimal = 1/2 fractional, an implied probability of 66.7%.