Decimal Odds Explained

Decimal Odds Explained

Continental Odds

Decimal, or ‘Continental odds’ as you might hear them described in some quarters, bear a close relationship with the fractions shown for fractional odds but perhaps not in quite the same relationship you might imagine from your dim recollections of school mathematics lessons. If you’re memory serves you well you may remember that any fraction could be written in decimal form too. So, for example 1/20 is just the fractional version of 0.05 (1 ÷ 20) and 3/2 would be 1.5 (3 ÷ 2). Simple stuff, yes? So it might be reasonable to guess that if you saw fractional odds of 3/2 then that would be decimal odds of 1.5, right? Wrong. And here’s why . . .

Decimal odds express the probability of an event happening in terms of the gross gain you’ll make from wagering on that event and it happening. So it represents the multiple of your stake that will be what is paid out to you if the bet wins. We’ll come back to this in a moment, but first let’s quickly discover how decimal odds can reveal the implied probability given to an event. This is super simple to deduce:

1 ÷ the decimal odds = the implied probability.

Using an example of decimal odds of 2.50 (observing the convention that decimal odds are usually expressed to two decimal places) that therefore translates to an implied probability of 1 ÷ 2.5 = 0.4. Multiplying that result by 100 to express it as a percentage gives us 40% probability.

Returning to the focus of what we’ll actually get paid from a bet listed with decimal odds, there’s a similarly easy calculation to make:

Your stake × the decimal odds offered = your gross gain if the bet is won.

Sticking with the example of a bet offered with decimal odds of 2.50 that means if you staked 3 credits, that bet would pay off as 7.5 credits if you won that bet. With fractional odds the distinction is that it represents the net gain. If we quickly unpack that using this example, the net gain here is 7.5 less the initial stake of 3 credits. That’s 4.5 credits. And that’s 1.5 times the stake, meaning the fractional odds would be 3/2. Which brings us neatly back to our opening paragraph to resolve the puzzle that expressing the fraction shown for fractional odds as a decimal does not give us the decimal odds – decimal odds focus is on the gross gain rather than the net gain from a wager, and to successfully convert fractional odds to decimal odds the rule is:

Numerator ÷ Denominator, then add ‘1’. Following this rule fraction odds of 3/2 thus translate to decimal odds of ((3÷ 2) + 1) = 2.50!

Even easier are the common fractional odds with a denominator of ‘1’, such as 10/1, 33/1 or 100/1. Those become decimal odds of 11.00, 34.00 and 101.00. You won’t need to reach for a calculator to convert those back and forth.