Sorry, but there's a bit of math involved when it comes to calculating sports betting value.(Photo credit: DonkeyHotey / Foter / CC BY)

Sports Gambling Plus Minus plus 100 spins at Betfair! Play Casino, Live casino, Sportsbook and Poker, all under one roof. About Realtime gaming mobile casinos. User Account Sign in. Permanent Wager: 25x Min deposit: €10 Code: RESOLUTION300. January 7, 2018. T&C. Filter by Casinos. 10 No Deposit Spins & £200 Bonus. Welcome to the Sports Betting Odds section of The Sports Geek. If you are new to sports betting and don’t understand how to read betting odds (+150, -110, +2200, etc) we will lay it all out for you and help you learn how the betting odds work.

Being able to convert betting odds into percentages is a major part of knowing how to read odds.

By knowing the percentage of the time you need to win a bet to break even, you can decide whether it is a smart bet to make. If you believe something has an 80% chance of occurring but the odds suggest it has a 50% chance of occurring, you have a positive expectation wager. If you believe something has an 80% chance of occurring but the odds suggest it has an 85% chance of occurring, it’s a bad bet to make because you have no edge.

Below are the formulas to convert moneyline betting odds to percentages, convert fraction betting odds to percentages, and convert decimal betting odds to percentages.

How to convert moneyline betting odds

Moneylines can come in ‘plus’ (favourites) and ‘minus’ (underdogs) formats, so there are two different formulas to convert moneylines into percentages.

For ‘plus’ moneylines, the formula is: 100 / (Moneyline + 100)

If the moneyline is +110, the formula would look like this:

Plus Minus In Gambling

100 / (110+100) = 100/210 = 0.476

Multiply your end result (0.476) by 100 to get the percentage: 47.6%

For ‘minus’ moneylines, the formula is: Moneyline / -(100 – (Moneyline))

If the moneyline is -130, the equation would look like this:

-130/ – (-130 -(-100)) = -130 / -230 = 130/230 = 0.565

Multiply your end result (0.565) by 100 to get the percentage: 56.5%

How to convert fraction betting odds

Fraction betting odds are easier to convert into an implied winning percentage.

For fraction betting odds, the formula is: Denominator / (Denominator + Numerator)

If the fraction betting odds are 11/10, the formula would look like this:

10 / (11+10) = 10 / 21 = 0.4761904

Multiply your end result (0.4761904) by 100 to get the percentage: 47.6%.

How to convert decimal betting odds

Plus Minus Symbol

Gambling Plus Minus 30

Decimal odds are the easiest to convert into a percentage.

For decimal betting odds, the formula is: 1 / decimal odds

If the decimal betting odds are 2.10, the equation would look like this:
1 / 2.10 = 0.4761904

Multiple your end result (0.4761904) by 100 to get the percentage: 47.6%.