How to read betting odds, with a real example

A decimal odd is what a winning bet returns for every 1 staked, stake included. At 3.80, a stake of 10 returns 38.00 if it wins: 28.00 of profit. If it loses, the 10 is gone.

return = stake × odd
profit = return − stake

Other formats are the same price written differently. Fractional odds of 5/2 and American odds of +250 are both 3.50 in decimal (5 ÷ 2 + 1, and 250 ÷ 100 + 1). The site and most European bookmakers use decimal.

Every price is also a claim about how often something happens. Divide 1 by the odd:

implied probability = 1 ÷ odd

1 ÷ 2.00 is 50%, 1 ÷ 3.80 is 26.3% and 1 ÷ 1.50 is 66.7%. It is also the break-even rate: if you bet at 3.80 over and over, the outcome has to happen more than 26.3% of the time for you to come out ahead.

Take Fenerbahçe v AS Roma in the UEFA Champions League on 10 September 2026, which finished 1–1. One bookmaker's 1X2 prices, from our odds archive, were 3.91, 3.80 and 1.95.

The three outcomes cover every possible result, so their probabilities should add up to 100%. They add up to 103.2%. The extra 3.2% is the bookmaker's margin, also called the overround, and it is how the bookmaker is paid whichever way the match goes.

Fair odds are the price with the margin taken out. The simplest way is to share the margin out in proportion: divide each implied probability by the total of 103.2%, then invert. For this match that gives 4.03, 3.92 and 2.01, in the last column. Each real price is a little shorter than its fair one, and that gap is what you pay to place the bet. Splitting the margin in proportion is one of several methods, so treat the result as an estimate of what the bookmaker thinks.

Fair odds can also be your own. If you believe a draw happens 30% of the time, the fair odd is 1 ÷ 0.30 = 3.33. The expected profit per 1 staked is probability × odd − 1:

at 3.50: 0.30 × 3.50 − 1 = +0.05
at 3.20: 0.30 × 3.20 − 1 = −0.04

A price above your fair odd has positive expected value, and one below it doesn't. The catch is that the 30% is an estimate, and a few points either way flips the sign. That is the whole difficulty of betting: nobody knows the true probability.

On our draw picks we show the odd taken, the median price of the other bookmakers for the same draw and the premium: how far our price sits above that median. It is the same idea as above, comparing prices instead of guessing results. The draw guide explains how picks are chosen, and the methodology page has the detail.