American odds are written as a plus or minus number built around a $100 bet: +150 means a $100 stake wins $150 profit, and -150 means you stake $150 to win $100. In the decimal odds Australian bookmakers quote, +150 is $2.50 and -150 is $1.67.
You meet them in US sports coverage and tools built for US markets, where a head to head price is called a moneyline. How betting odds work explains the decimal maths they convert into.
Plus odds: the profit on $100
A plus number is the profit on a $100 stake: +150 pays $150 and +260 pays $260. For any stake, profit = stake x plus odds / 100. With an illustrative $40 at +150, the profit is 40 x 150 / 100 = $60, and the bet returns $100.
Any plus number above +100 is odds against, a price over $2.00.
Minus odds: the stake to win $100
A minus number is what you have to stake to win $100: at -150 you stake $150, and at -110 you stake $110. For any stake, profit = stake x 100 / the minus number without its sign. With an illustrative $30 at -150, the profit is 30 x 100 / 150 = $20, and the bet returns $50.
Any minus number beyond -100 is odds-on, under $2.00, and the bigger the number, the shorter the price. Even money is the one price written both ways: +100 or -100.
Converting plus and minus odds to decimal
- decimal odds from a plus number = plus odds / 100 + 1
- decimal odds from a minus number = 100 / (minus odds without the sign) + 1
With illustrative prices:
| American | Working | Decimal | Implied chance |
|---|---|---|---|
| -275 | 100 / 275 + 1 = 1.364 | $1.36 | 73.3% |
| -150 | 100 / 150 + 1 = 1.667 | $1.67 | 60.0% |
| -110 | 100 / 110 + 1 = 1.909 | $1.91 | 52.4% |
| +100 or -100 | 100 / 100 + 1 = 2.000 | $2.00 | 50.0% |
| +150 | 150 / 100 + 1 = 2.500 | $2.50 | 40.0% |
| +260 | 260 / 100 + 1 = 3.600 | $3.60 | 27.8% |
Each implied chance is 1 / the decimal before rounding: 1 / (100 / 150 + 1) = 60.0%. The odds converter also runs the sums in reverse, and fractional odds convert through the decimal price too.
Why -110 is $1.91
-110 means $110 staked to win $100, a $210 return, so the decimal price is 210 / 110 = 1.909, shown as $1.91. It is the standard US quote on both sides of a line (the US calls it a spread) or a total. Two sides at -110 imply 52.38% each, 104.76% in all, and a run of bets at -110 has to win 52.4% of the time to break even. US betting terms maps spread, parlay and juice to the Australian words.
Moneyline odds
A moneyline is the US name for a head to head bet: you pick the winner, with no start. Moneyline odds are American odds on that market. With an illustrative NBA game:
| Team | Moneyline | Decimal | Implied chance |
|---|---|---|---|
| Team A | -145 | $1.69 | 59.2% |
| Team B | +125 | $2.25 | 44.4% |
Working for Team A: 100 / 145 + 1 = 1.690, and 1 / 1.690 = 59.2%. The two chances add up to 103.6%, and the 3.6 points over 100% are the bookmaker's margin.
Mistakes reading American odds
| Mistake | What it costs | The fix |
|---|---|---|
| Treating -150 as a long price | $30 at -150 wins $20, not the $45 that +150 would pay | A minus sign means you stake more than you win |
| Judging two prices by the gap between the numbers | +110 and -110 look 220 apart, yet $2.10 returns only 10% more than $1.91 | Convert both to decimal, then divide |
| Converting a rounded decimal back | $1.67 gives -100 / 0.67 = -149, not -150 | Convert from the American number itself |
Converting US odds before you compare prices
Put a price from US sports coverage into decimal before you set it beside the prices on B337's Terminal. The Terminal shows prices from 40+ bookmakers across racing and sports; on its sports board, bookmakers sit side by side on head to head, line and total markets for the NBA and other leagues whenever markets are up.
Prices refresh on a repeating cycle, not tick by tick, so check the price in your bookmaker account before you bet. A free account opens a limited view of the Terminal with live odds.
Risk: Betting involves risk. A converted price tells you what a bet pays and what it implies, never who will win, and there is no guarantee of profit at any price. See responsible gambling for limits and support.