DraftKings' betting glossary provides a current US operator reference for this notation. The calculations below separate the sign convention from implied probability, total return, and favourite status.
How Plus Odds Work
A plus sign means the number is the profit on a 100 unit stake.
+250 means a 100 pound stake returns 250 pounds profit, plus your 100 pound stake back, for a total of 350 pounds.
Illustrative examples:
- +320: a 10 unit stake profits 32 units (42 total return)
- +240: a 10 unit stake profits 24 units (34 total return)
- +500: a 10 unit stake profits 50 units (60 total return)
The formula for plus odds is:
Profit = Stake x (American Odds / 100)
How Minus Odds Work
A minus sign means the absolute number is the stake needed to win 100 units of profit.
-200 means you need to stake 200 pounds to win 100 pounds profit. Your total return would be 300 pounds.
Illustrative examples:
- -250: a 10 unit stake profits 4 units (14 total return)
- -180: a 10 unit stake profits 5.56 units (15.56 total return)
The formula for minus odds is:
Profit = Stake x 100 / |American odds|
Converting American Odds
To Decimal Odds
For plus odds: (American Odds / 100) + 1
- +250 becomes (250 / 100) + 1 = 3.50
For minus odds: (100 / |American Odds|) + 1
- -200 becomes (100 / 200) + 1 = 1.50
To Fractional Odds
For plus odds: Express the number over 100 and simplify.
- +250 becomes 250/100, simplified to 5/2
For minus odds: Express 100 over the number and simplify.
- -200 becomes 100/200, simplified to 1/2
To Implied Probability
For plus odds: 100 / (American Odds + 100) x 100
- +250: 100 / 350 x 100 = 28.6%
For minus odds: |American Odds| / (|American Odds| + 100) x 100
- -200: 200 / 300 x 100 = 66.7%
Quick Reference Table
| American | Decimal | Fractional | Implied Probability |
|---|---|---|---|
| -400 | 1.25 | 1/4 | 80.0% |
| -200 | 1.50 | 1/2 | 66.7% |
| -110 | 1.91 | 10/11 | 52.4% |
| +100 | 2.00 | Evens | 50.0% |
| +150 | 2.50 | 3/2 | 40.0% |
| +250 | 3.50 | 5/2 | 28.6% |
| +500 | 6.00 | 5/1 | 16.7% |
Important Distinction
In a two-outcome, no-draw market, a negative price will normally be the shorter side and a positive price the longer side. In a three-outcome football market, all three selections can have positive American prices. Use the converted decimal price to compare payoffs; do not infer the number of market outcomes from the sign.
Past performance does not guarantee future results. Changing odds format changes presentation, not the underlying payoff.
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Related resources
Continue with Decimal Odds: What They Mean in Betting for the next part of this topic, or return to Betting Glossary: Every Betting Term Explained in Plain English to compare the other guides in this collection.
Continue learning
- Next guide: Ante-Post Betting
- Related guide: Asian Handicap Explained
- Go deeper: Odds Conversion Guide
Assumptions and limitations
The 100-unit figures explain the American-odds formula; they are not suggested stakes. Conversions can differ slightly after display rounding, but changing format does not change the underlying accepted payoff. DraftKings' glossary is one US operator reference, not a universal settlement rule.
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