One of the three ways of specifying betting odds is the American odds, also called US odds. The other two
are Decimal odds and Fractional odds. Two prominent and significant features that distinguish American odds
from the other two are: one, they are preceded by a plus (+) or a minus (-) sign, and two, their values are always greater than or equal to 100.
These signs placed before American odds are NOT mathematical signs; they are simply symbols that indicate, as will be seen shortly, whether winnings are more than or less than stakes.
Whenever there is a bet to be placed on an event between two contestants, such as a sports match between two teams, the first thing that has to be considered
is if the two contestants are of equal strength, or if one of them is more favored to win the match than the other. The first case
is known as Evens betting and each one is assigned similar odds. If one of the teams is a favorite and the other the underdog, then
the odds assigned to the favorite is called Odds-on, and that to the underdog Odds-against.
Unlike the other two odds specification methods, American odds explicitly distinguish whether winnings are less than or more than the stakes; and that is
exactly the purpose of the + and - signs as will be seen in the definitions below. Consequently, there is one definition of American odds
for each of the two cases.
Definitions of American Odds
The definitions of each are listed below together with how to calculate the winnings and the pay-outs of a bet. Winnings are what the bettor wins with a certain
stake (wager), while pay-outs are the total amount paid to the winner. Obviously, pay-outs are winnings plus stakes.
Negative American Odds are representations of how much to wager in order to win $100.
For example, odds of -150 mean that in order to win $100, the wager must be $150.
Negative American Odds are used when winnings are less than stakes, which is normally the case of a favorite team.
Winning = Stake * 100/negative American Odds
Pay-out = Stake * (100/negative American Odds + 1)
Winning + Stake
Positive American Odds are representations of how much the winnings will be when $100 are wagered.
For example, odds of +150 mean that $150 will be won, when $100 are wagered.
Positive American Odds are used when winnings are more than stakes, which is normally the case of a underdog team.
Winning = Stake * positive American Odds/100
Pay-out = Stake * (positive American Odds/100 + 1)
= Winning + Stake
Some Common American Odds Examples
American Odds for Evens Betting
The simplest case of betting is when the betting is between friends (fair bet) and when the two teams, say, team A and team B, are competitive.
In this case since no sportsbook commission is involved you bet $1 to win $1. And the odds are given as,
Team A : +100
The + an - signs have no significance here. You can even put both as + or both as -.
Team B : -100
However, if the bets are placed through a sportsbook, although both teams are equally strong, because of the commission involved, the
winnings will be less than the stakes for both teams. Usually, sportsbooks present these odds as 110 or 111, thus,
Team A : -110
Team B : -110
If you bet $30 on either team, using the formula given above, you'll win $30*100/110 = $27.27, and with your wager, the pay-out would be $57.27.
American Odds for Moneyline Betting
If there is a disparity of strength between the two teams, one of them will certainly be favored over the other. In the US, Moneyline is betting without point spreads.
There is nothing special about it; it is just a win or lose betting. For example, odds of a match between teams C and D may be specified as,
Team C : -375
Team D : +280
If you bet $30 on team C, using the formula of - odds given above, you'll win $30*100/375 = $8.00, and with your wager, the pay-out would be $38.00.
If you bet $30 on team D, using the formula of + odds given above, you'll win $30*280/100 = $84.00, and with your wager, the pay-out would be $114.00.
Note that if no commissions were involved, the odds would have been -300 and +300, respectively, for team C and team D
American Odds for Point-spread Betting
Point-spread is a way of equalizing the odds of two non-equal teams by introducing a handicap. As demonstrated in the above example, there will be
very little to be gained by betting on the favorite team C, and a lot by betting on the underdog. Bettors will usually stay away from such bets since
it is a risky bet in either case, plus it will be a lot of loss for the sportsbook if team D wins. To overcome this, a handicap of, say 5 points,
will be introduced so that both odds would be equal as in the case of evens. Such odds may be specified as,
Team C : +5 -110
Team D : -5 -110
In this case, if you bet on team C, you'll win the bet if team C wins or even if it loses by less than 5 points. If you bet on team D, you'll win the
bet if team D wins by more than 5 points; if team D wins by by 4 points, yes, you have correctly predicted the winner, but it hasn't "covered the spread"
and you lose. If team D wins by exactly 5 points, it will be a push, and the wager will will be returned to the bettors.
Conversion of American Odds to Decimal and Fractional Odds
The easiest way to convert odds is to use an odds conversion table. However, since such tables may not be always available,
the bettor has to memorize the following steps of conversion from American odds to Decimal and Fractional odds.
To convert from American Odds to Decimal Odds
Obviously, we have to consider the cases of - odds and + odds.
- In the case of - odds, divide 100 by the American odds and add 1. For example, to convert the American odds of -375 to Decimal, 100/375 + 1 = 1.27.
- In the case of + odds, divide the American odds by 100 and add 1. For example, to convert the American odds +280 to Decimal, 280/100 + 1 = 3.8.
To convert from American Odds to Fractional Odds
Again, we have to consider the cases of - odds and + odds.
- In the case of - odds, just write in the form 100/American, and simplify if you can. For example, the American odds of -375 will be 100/375, and after simplification, 4/15.
- In the case of + odds, just write in the form American/100, and simplify if you can. For example, American odds of +280 will be 280/100, and after simplification, 14/5.
Betting Calculator for American Odds
If you do not want to go through all the trouble of conversions and calculations, the following betting calculator may make
your life easier. Just enter your stake, choose the odds, and click on the 'Calculate' button.