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Odds Converter
Convert between decimal, American, fractional, and implied probability formats. Enter any format and see all others instantly.
Load a common format first
Use a familiar sportsbook or prediction-market example, then tweak the source field you actually work in.
e.g. 2.50 (used by most global sportsbooks)
e.g. +150 or -200 (US sportsbooks)
e.g. 3/2 or 5/1 (UK bookmakers)
e.g. 40.0% (prediction markets use this)
e.g. 40¢ = 40% implied probability (Kalshi, Polymarket)
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A 2.50 decimal price returns $250 on a $100 stake, for $150 profit.
Payout on $100 bet
If Win
$250
Profit
$150
If Lose
-$100
Common odds conversions
| Decimal | American | Fractional | Implied % | PM Price |
|---|---|---|---|---|
| 1.25 | -400 | 1/4 | 80.0% | 80¢ |
| 1.50 | -200 | 1/2 | 66.7% | 67¢ |
| 2.00 | +100 | 1/1 | 50.0% | 50¢ |
| 2.50 | +150 | 3/2 | 40.0% | 40¢ |
| 3.00 | +200 | 2/1 | 33.3% | 33¢ |
| 5.00 | +400 | 4/1 | 20.0% | 20¢ |
| 10.00 | +900 | 9/1 | 10.0% | 10¢ |
Frequently asked questions
Everything you need to know about odds formats.
How do I convert decimal odds to American odds?
For decimal odds of 2.00 or higher: American = (decimal - 1) x 100. For decimal odds below 2.00: American = -100 / (decimal - 1). Example: 2.50 decimal = +150 American. 1.50 decimal = -200 American.
How do I calculate implied probability from odds?
For decimal odds, implied probability is simply 1 divided by the decimal price. Example: 2.50 odds imply 40.0% because 1 / 2.50 = 0.40. Positive American odds use 100 / (odds + 100), while negative American odds use |odds| / (|odds| + 100).
What odds format do prediction markets use?
Prediction markets like Kalshi and Polymarket display prices as cents (0-100¢), which directly represent the implied probability. A contract at 65¢ implies a 65% probability. This is equivalent to 1.538 decimal odds or -186 American odds. EVSignals normalizes all formats.
Compare odds across 500+ sources automatically
EVSignals normalizes odds from Kalshi, Polymarket, sportsbooks, and more into a single schema. No manual conversion needed.