Betting with Bookie: Introduction to Odds

Betting with Bookie is an ongoing educational series designed to demystify the betting experience. Each article will tackle sports betting terminology and concepts in a simple way, in an effort to make you a better bettor.

If you’ve ever visited an online sportsbook or betting exchange then you know they often list multiple odds formats. In some cases the default format is simply the name of the country in which it originated or is most popular - American, Hong Kong, Malaysian, and Indonesian odds - which all work in different ways.

Other times the format is more straightforward, like Decimal and Fractional odds. No one format is more right or more wrong than the others; it’s often just a matter of preference.

Regardless of format, one thing is always true: the less likely an outcome, the bigger the reward. Because of this, understanding how to read various odds formats, and knowing how to convert between them, is an important element to successful betting.

This article will give you a better understanding of the three most common formats.

Decimal Odds
For many people Decimal odds are the easiest to read and understand, and almost every sportsbook or betting exchange will let you set this display.

There’s no secret formula when figuring out your potential winnings off Decimal odds. For example, if Manchester United has odds of 2.5 to win and you stake $10 on them to win, your potential payout is calculated as follows:

Stake x Odds = Potential Payout
or
$10 x 2.5 = $25.00

Your profit in this example is your payout ($25) less the stake ($10), for a total of $15. Pretty straightforward.

Fractional Odds
Where Decimal odds are typically available worldwide, Fractional odds are most popular in the United Kingdom, especially with horse racing.

Calculating potential winnings is slightly more involved with Fractional odds, but they are still based on simple math. This time Manchester United’s odds win are 5/2. You can do the math a couple different ways, but the starting point will look familiar: Stake x Odds = Payout.

Route #1: $10 x 5/2 = $10 x 2.5 = $25.00

Route #2: $10 x 5/2 = ($10 x 5) / 2 = $50 / 2 = $25.

Importantly, the outcome is exactly the same as using Decimal odds, with a $15 profit if your bet wins.

American Odds
Throw everything you just learned out the window! Okay, don’t actually do that, but American odds is where heads start spinning if you’ve never seen them before. This is where you see numbers like +220, -550, +180, and so on. But what does it all mean?

American Odds take two different approaches to betting, by showing odds as either positive or negative numbers. Positive odds ask the question, “If I risk $100, how much will I win?” Using the same example as above, Manchester United has odds of +150 to win.

+150 odds x $10 = $15 profit.

But what if the number is negative: Manchester United -150? When you see this, ask “How much do I have to risk in order to win $100?” So, to turn a $100 profit you would have to risk $150. In keeping with our other examples with a $10 wager,

-150 odds x $10 = $6.67 profit

The following table shows some commonly seen odds, how they translate between formats, and their implied probably - that is, the chance of a particular event happening.

Decimal	Fractional	American	Implied Probability
1.01	1/100	-10000	99%
1.1	1/10	-1000	90.9%
1.5	1/2	-200	66.7%
1.8	4/5	-125	55.6%
2.0	1/1	-100	50%
2.5	6/4	+150	40%
3.0	2/1	+250	33.3%
5.0	4/1	+400	20%
10.0	9/1	+900	10%
100.0	99/1	+9900	1%

Thankfully, most online sportsbooks and betting exchanges will allow you to choose from a list of odds formats so you can choose whichever you’re most comfortable using.

A final tip: toggling from one odds format to another won’t magically increase your potential winnings. Find the odds format that you understand most easily and stick with that - it will help you make quick, sound judgements on where the value lies in the odds on offer.

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