Depending on your location, here are the two types of sports betting odds you need to be familiar with:

Fractional Odds

Most commonly found in the United Kingdom and Ireland, these odds quote the net total paid out to the  relative to his or her stake. For example, odds of 2/1 (read “two-to-one” or 2:1) means the punter  will make a £200 profit on a £100 wager. On the contrary, if the odds are 1/2, the  will make £50 on a £100 wager. However, the  always receives the original wager back. So, with 2/1 odds, the punter would get a total of £300 (£200 plus the original £100). Odds of 1/1 are known as even money or evens. Fractional odds are also known as UK odds, British odds or traditional odds within the country.

Decimal Odds

Most common in continental Europe, Australia and Canada are decimal odds. Unlike in fractional odds, the punter must give up the stake in order to make a bet. The figure quoted is the winning amount paid out to the punter.  So, the decimal odds of an outcome are equivalent to the decimal value of the fractional odds plus one.  For example, even odds 1/1 are 2 in decimal odds. The 2/1 fractional odds mentioned above are now 3, and the 1/2 odds are 1.5.

Decimal odds work well for parlay betting because the odds to be paid out are the product of the odds for each outcome wagered upon. A parlay bet is a single bet that links together two or more individual wagers and is dependent on all of those wagers winning together. Decimal odds are the easiest to work with when trading so they are common in betting exchanges, or peer-to-peer gambling. They are known as European odds, or continental odds in the UK.

Conversion Formulas

Decimal to Fractional = Decimal-1, then convert to fraction

Fractional to Decimal = Divide fraction, then add 1

Sports Betting Lines

The common misnomer about sports betting lines is that they look backwards. But, the favourite to win actually has a minus sign (-) and the underdog has a plus sign (+). So, if you bet the negative money line, you win less than your wager. If you bet the positive money line, you win more than your wager.

Sports betting lines are made up by oddsmakers, not bookies (bookmakers which take your bet), based on the previous records and other variables like injuries and weather. The line will also change if there are too many punters on one side. Line adjustments are made up until the start time of the sporting event so it can get a little crazy. Remember that bookies work on a commission. They want to end up having each side of the line even so the losers end up paying the winners. If the lines are not even, they pay out of commissions. Try to decipher whether a line change is because of a variable related to the event or because of uneven betting lines.