American Odds Explained: What Plus and Minus Mean
Most explanations stop at the 100-unit convention and leave the reader to work out an actual bet. That is the wrong place to stop, because almost nobody stakes exactly 100.
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What the sign is telling you
American odds carry two pieces of information in one number: the direction of the price and the size of the return. Smarkets states the convention directly:
“American odds, also known as money line or US odds, are expressed with either a positive or negative number”
And the two branches:
“A negative number indicates what you must bet to make £100 profit, while a positive number indicates how much you might profit if you bet £100”
So a minus number is a stake requirement and a plus number is a profit figure. They are measured against the same 100-unit reference, which is why they can be compared at all. Caesars describes the same two-part reading from the US side:
“The number next to each team tells you 2 things at once: which side the market favors and how much you stand to profit on a correct pick”
The word most articles reach for here is "favourite". That is a description of the market's opinion, not a rule. A minus price means the raw implied probability of that outcome is above 50 per cent, and that figure still contains the operator's margin, so it is not the market's own view of the chance. It certainly does not mean the outcome will happen.
The two payout formulas
The 100-unit convention is a display choice. Your stake is whatever you type in, and Smarkets says so explicitly:
“It's important to understand that you don't need to bet the amount equal to the money line - you can bet more or less, with the return linked to your stake”
Two formulas cover every American price. Use the absolute value of the number and pick the branch by its sign.
For a minus price:
profit = stake × (100 / |odds|)
For a plus price:
profit = stake × (odds / 100)
Total return is stake + profit on both branches, because American odds quote
profit and never include the stake.
Return laboratory
Both branches on a 50-unit stake
profit = stake × (100 / |odds|) when minus, stake × (odds / 100) when plusTotal return adds the stake back: 95.45 units at -110 and 175.00 units at +250. Keep the unrounded quotient through the calculation and round only the figure you display.
The single most common arithmetic mistake is treating a minus price as a percentage. At -110 the deduction is not ten per cent. The profit ratio is 100 divided by 110, which is 0.9091, so a 50-unit stake wins 45.45 rather than 45.00.
American price ladder
Every row below is the same bet size, so the column you should read is total return. This is the table to keep open while you compare two sportsbooks.
| American price | Decimal | Fractional | Profit on 50 units | Total return |
|---|---|---|---|---|
| -400 | 1.25 | 1/4 | 12.50 | 62.50 |
| -200 | 1.50 | 1/2 | 25.00 | 75.00 |
| -110 | 1.91 | 10/11 | 45.45 | 95.45 |
| +100 | 2.00 | 1/1 | 50.00 | 100.00 |
| +150 | 2.50 | 3/2 | 75.00 | 125.00 |
| +250 | 3.50 | 5/2 | 125.00 | 175.00 |
| +600 | 7.00 | 6/1 | 300.00 | 350.00 |
- Decimal
- 1.25
- Fractional
- 1/4
- Profit on 50 units
- 12.50
- Total return
- 62.50
- Decimal
- 1.50
- Fractional
- 1/2
- Profit on 50 units
- 25.00
- Total return
- 75.00
- Decimal
- 1.91
- Fractional
- 10/11
- Profit on 50 units
- 45.45
- Total return
- 95.45
- Decimal
- 2.00
- Fractional
- 1/1
- Profit on 50 units
- 50.00
- Total return
- 100.00
- Decimal
- 2.50
- Fractional
- 3/2
- Profit on 50 units
- 75.00
- Total return
- 125.00
- Decimal
- 3.50
- Fractional
- 5/2
- Profit on 50 units
- 125.00
- Total return
- 175.00
- Decimal
- 7.00
- Fractional
- 6/1
- Profit on 50 units
- 300.00
- Total return
- 350.00
Read the ladder in both directions. Downwards it shows how quickly profit grows once a price crosses into plus territory. Upwards it shows how much stake a short minus price consumes for a small return, which is the part that decides whether a parlay leg is worth adding.
Convert to decimal and fractional
Conversion is the only reliable way to compare an American price with a European or British one, because the underlying price is identical in all three displays. Smarkets puts the point plainly:
“No matter the format used, the probability is always the same. It's just the presentation that differs”
To decimal:
- plus price:
(odds / 100) + 1, so +205 becomes 3.05; - minus price:
(100 / |odds|) + 1, so ‑200 becomes 1.50.
The added one is not decoration. Smarkets explains why it belongs there:
“As with the fractional odds conversion, the one is added in respect of the stake not being included in the return with American odds, but being included for decimals”
To fractional, drop the one and reduce:
- plus price:
odds / 100, so +250 becomes 5/2; - minus price:
100 / |odds|, so ‑110 becomes 10/11.
Two conversions catch people out. A minus price always produces an odds-on fraction with the larger number underneath, and -110 does not reduce to a tidy fraction, which is exactly why American books display it as -110 in the first place. The fractional odds guide covers reading and reducing fractions in full.
The gap around even money
There is no American price between -100 and +100, and there is no such thing as zero odds. Both -100 and +100 describe the same price: risk 100 to win 100, decimal 2.00, fractional 1/1. Almost every sportsbook displays that price as +100 and never as -100, so the ladder simply jumps from ‑101 to +100.
This matters when you sort a list of prices by number. Sorting -400, -110, +100 and +250 numerically puts +100 and +250 above -110, which is the correct order by return, but sorting -400 and -110 numerically puts -400 first even though it is the worse price for a backer. Convert before sorting, and sort on decimal odds.
Comparing two American prices
Between two minus prices, the one closer to zero is better for you. Between two plus prices, the larger number is better. Across the boundary, any plus price beats any minus price on return, though not on strike rate.
| Two books on the same selection | Better for a backer | Why |
|---|---|---|
| -105 against -115 | -105 | Risks 105 rather than 115 for the same 100 profit. |
| +240 against +250 | +250 | Ten more units of profit per 100 staked. |
| -102 against +100 | +100 | Decimal 2.00 against 1.98, so the plus price returns more. |
| +100 against -100 | Neither | Same price shown two ways, decimal 2.00 in both cases. |
- Better for a backer
- -105
- Why
- Risks 105 rather than 115 for the same 100 profit.
- Better for a backer
- +250
- Why
- Ten more units of profit per 100 staked.
- Better for a backer
- +100
- Why
- Decimal 2.00 against 1.98, so the plus price returns more.
- Better for a backer
- Neither
- Why
- Same price shown two ways, decimal 2.00 in both cases.
The difference between -105 and -115 looks small and is not. On a 50-unit stake the profit is 47.62 against 43.48, a gap of 4.14 units, or just over nine per cent of the profit on every winning bet you place at that line.
Displayed price versus accepted price
None of this arithmetic protects you if the number moved between the screen and the bet slip. Operator rules are explicit that the displayed price is informational until the bet is taken:
“All odds displayed are for information purposes only and are subject to change. Only odds available at the actual time a bet is accepted shall be valid”
So the price to record is the one printed on the receipt, not the one you clicked. If your settled return does not match your arithmetic, check the accepted price first, before assuming a settlement error. On a horse race there is a second reason the two can differ, and it is covered in the Rule 4 deductions guide.
Ownership boundary
This page owns reading a plus or minus price and turning it into money. Three neighbouring questions are answered elsewhere so that neither page has to half‑cover the other:
- Moneyline bet rules for what the bet settles on, including draws, overtime and shortened games.
- Bookmaker margin and overround for why a complete set of prices adds to more than 100 per cent.
A price is a percentage before it is a payout
Turn -110 into 52.38 per cent and find the strike rate that makes the bet break even.
Evidence manifest4 primary sources mapped to this guideView sources
Each source below is retained with the claims it supports. Operator sources describe published terms, not independent first‑hand performance.
- Smarkets help centre, what are the different betting odds formats (opens in a new tab)
- American odds, also known as money line or US odds, are expressed with either a positive or negative number
- A negative number indicates what you must bet to make £100 profit, while a positive number indicates how much you might profit if you bet £100
- It's important to understand that you don't need to bet the amount equal to the money line - you can bet more or less, with the return linked to your stake
- No matter the format used, the probability is always the same. It's just the presentation that differs
- Smarkets help centre, how to convert betting odds (opens in a new tab)
- To convert positive American odds the equation is:
- As with the fractional odds conversion, the one is added in respect of the stake not being included in the return with American odds, but being included for decimals
- Caesars Sportsbook betting guide, moneyline (opens in a new tab)
- The number next to each team tells you 2 things at once: which side the market favors and how much you stand to profit on a correct pick
- American odds are the standard odds format for sports betting in the U.S.
- Sky Bet market rules, placing bets (opens in a new tab)
- All odds displayed are for information purposes only and are subject to change. Only odds available at the actual time a bet is accepted shall be valid
FAQ
What does plus and minus mean in betting odds?
A minus number is the stake required to win 100 units, so -150 risks 150 to win 100. A plus number is the profit on a 100-unit stake, so +150 wins 150. Minus marks the side the market prices above even money and plus marks the side priced below it.
How much do I win on a bet at -110?
Profit is stake multiplied by 100 divided by 110, which is 0.9091 per unit. A 50-unit stake wins 45.45 and returns 95.45 including the stake. A 110-unit stake wins exactly 100.
What does +110 mean?
It means 110 units of profit for every 100 staked, decimal 2.10 and fractional 11/10. A 20-unit stake at +110 wins 22 and returns 42.
Is a plus price always better than a minus price?
It returns more per unit staked, which is not the same as being better. A plus price also implies a lower chance of winning, so the two only become comparable once both are converted to implied probability and compared with your own estimate.
How do I convert American odds to decimal odds?
Divide a plus price by 100 and add one, so +250 becomes 3.50. Divide 100 by the absolute value of a minus price and add one, so -200 becomes 1.50. The added one accounts for the stake, which decimal odds include and American odds do not.