Odds Converter: Decimal, Fractional and American, With Implied Probability
Type a price in any format and the odds converter fills in the other two, plus the number that actually matters: the implied probability the price is charging you for. Indian apps quote decimal almost everywhere, but exchanges, UK sites and American content still speak their own dialects.
How the Three Odds Formats Relate
Decimal odds state the total return per rupee staked: 2.50 pays ₹2.50 back for every ₹1, stake included. Fractional odds state profit against stake: 6/4 means ₹6 profit for every ₹4 staked, which is the same price as decimal 2.50. American odds pivot around 100: +150 is the profit on a 100-unit stake, while −200 is the stake needed to win 100. Same probability, three costumes.
The conversion arithmetic is short. Decimal = fractional + 1 (after dividing the fraction out). Positive American ÷ 100 + 1 gives decimal; for negative American, 100 ÷ |odds| + 1. And implied probability is always 1 ÷ decimal. That last one is the only formula worth memorising, because every value judgement starts there. The odds guide walks through why, and Odds IQ lets you practise it with a virtual bankroll.
Quick reference table
| Decimal | Fractional | American | Implied probability |
|---|---|---|---|
| 1.50 | 1/2 | −200 | 66.7% |
| 1.91 | 10/11 | −110 | 52.4% |
| 2.00 | 1/1 (evens) | +100 | 50.0% |
| 2.50 | 6/4 | +150 | 40.0% |
| 3.40 | 12/5 | +240 | 29.4% |
| 9.00 | 8/1 | +800 | 11.1% |
Frequently Asked Questions
How do I convert decimal odds to implied probability?
Divide 1 by the decimal odds. Odds of 2.50 give 1 ÷ 2.50 = 0.40, so 40%. If your own estimate of the real chance is higher than that number, the price is value; if lower, pass.
Which odds format do Indian betting apps use?
Decimal, almost universally: it is the default across the apps on our rankings. You will meet fractional odds on UK-facing sites and exchange commentary, and American odds in US content, which is exactly when a converter earns its keep.
What does a negative American price like −200 mean?
You must stake 200 to win 100, marking a favourite. It converts to decimal as 100 ÷ 200 + 1 = 1.50, an implied 66.7%. Positive prices mark underdogs and count profit per 100 staked instead.
Why do the implied probabilities of both sides add past 100%?
That excess is the bookmaker's margin, or overround. Two sides at 1.90 each imply 52.6% + 52.6% = 105.3%; the 5.3% is what the book earns over time regardless of the result. The margin calculator measures it for any market you paste in.
Is this odds converter free and does it store anything?
Free, no signup, and it stores nothing about your inputs. The page even keeps working offline once loaded, since the conversion runs entirely in your browser.
What are the best odds formats for beginners?
Decimal, without contest. The mental arithmetic is one multiplication (stake × odds = return) and the implied probability is one division. Learn decimal first, use this converter for everything else, and graduate to reading margins when the basics feel automatic.
Related: the accumulator calculator for multi-leg maths, and the margin calculator for pricing a whole market.