Betting Odds Calculator and Converter
Type odds in any format and the calculator shows them in the others, the chance they imply and what your stake returns. It can also add up a whole market to show the margin built into it, and multiply selections into one combined bet.
What the converter does
Odds are one fact written in different ways. Decimal odds, fractional odds, American odds and a plain chance all say how much a bet pays and how often it must win to break even. The converter turns any one of them into the other three, shows what a stake returns, adds up a whole market to reveal its margin, and multiplies selections into one combined bet.
It uses only the figures you type. It does not know any bookmaker’s or game’s odds, and it cannot tell you the real chance of anything.
How to use it
Pick what you want to work out and the format you are typing in. For one set of odds, type them, add a stake and read the tiles: the same odds in every format, the chance they imply, and what the stake returns and gains. The table underneath shows common stakes. The optional box takes your own estimate of the real chance: type 36 for odds of 2.50 and the converter shows that ₹100 comes back as ₹90 on average, so the bet keeps 10%. To check a market, type the odds of every outcome of one event. To combine selections, type the odds of each.
The four formats on one page
The starting example is decimal odds of 2.50, an illustration rather than any real price. It means ₹250 comes back for every ₹100 staked, a gain of ₹150.
| Decimal | Fractional | American | Chance it implies |
|---|---|---|---|
| 1.50 | 1/2 | −200 | 66.67% |
| 1.91 | about 10/11 | −110 | 52.36% |
| 2.50 | 3/2 | +150 | 40.00% |
| 3.00 | 2/1 | +200 | 33.33% |
| 4.00 | 3/1 | +300 | 25.00% |
Decimal odds include your stake. Fractional odds leave it out and give the gain against the stake: 3/2 gains ₹3 for every ₹2. American odds say how much you gain on ₹100 (plus) or how much you must stake to gain ₹100 (minus). The chance is 1 divided by the decimal odds, the share of the time the bet has to win just to break even.
Going the other way works the same. American odds of −150 mean you stake ₹150 to gain ₹100. That is decimal odds of 1.67 and fractional odds of 2/3, and the bet has to win 60% of the time to break even. A ₹100 stake gains ₹66.67 and returns ₹166.67.
Where the margin hides
Take a market with two outcomes priced at 1.90 each. Each implies 52.63%, and together they add up to 105.26%. A market with no margin would add up to 100%. Spread ₹100 over both outcomes in proportion to their implied chances and ₹95 comes back whichever one wins, so the market keeps 5%. Two other examples, both illustrations: odds of 1.85 and 2.05 add up to 102.83% and keep 2.76%, and three outcomes at 2.4, 3.3 and 3.1 add up to 104.23% and keep 4.06%.
Combined bets pile the margin up. Four selections at 1.90 multiply to 13.03, and the implied chance of all four winning is 7.67%. If each were a fair 50–50 shot, the real chance of all four would be 6.25%, and ₹100 would come back as ₹81.45 on average. The bet would keep 18.55%, against 5% on each single selection.
What the implied chance does not mean
The implied chance is a break-even line, not a forecast. A bet gains money on average only if its real chance is above that line, and nobody can read the real chance off the odds. Because a margin is built in, the implied chances of a market are a little higher than the fair ones, which the market table shows column by column.
What it cannot tell you
It cannot say whether odds are good, whether a market lists every outcome, or what a game’s rules do in a tie or a void round. It ignores fees and taxes unless you fold them into the odds you type, so use the odds your own screen shows. It predicts nothing. For the cost of playing many rounds, use the expected-loss calculator. The probability calculator turns a chance into the odds of at least one in many tries, and the win rate calculator tests a record against the break-even line. See how a crash game’s edge works in the Aviator odds calculator, and read why no predictor beats the odds. More checks sit with the other free tools.
Common questions
How do I turn decimal odds into a percentage chance?
Divide 1 by the decimal odds. Odds of 2.50 give 1 ÷ 2.5 = 40%. That is the implied chance, the chance at which the bet breaks even. The real chance can be higher or lower, and the odds alone cannot say which.
What is the difference between +150 and −150 in American odds?
+150 means a ₹100 stake gains ₹150, which is decimal odds of 2.50 and an implied chance of 40%. −150 means you stake ₹150 to gain ₹100, which is decimal odds of 1.67 and an implied chance of 60%. The plus side is the less likely one.
How do I change fractional odds like 5/2 into decimal odds?
Divide the top number by the bottom and add 1. For 5/2, 5 ÷ 2 = 2.5, and 2.5 + 1 = 3.50. The 1 is your stake, which decimal odds include and fractional odds leave out. So ₹100 at 5/2 gains ₹250 and returns ₹350.
Why do the chances in a market add up to more than 100 per cent?
The extra is the margin built into the odds. Two outcomes at 1.90 each imply 52.63% apiece, which add up to 105.26%. Spread ₹100 over both and ₹95 comes back whichever wins, so the market keeps 5%. Without a margin the same two outcomes would pay 2.00 each.
How much does a combined bet of several selections pay?
Multiply the decimal odds of every selection. Four selections at 1.90 give 13.03, so ₹100 returns ₹1,303.21 if all four win and nothing if even one loses. Each selection added makes the payout bigger and the chance of getting it smaller.
Is anything I type into the odds converter uploaded or saved?
No. The conversions are worked out in your browser and nothing is stored. If you press the copy-link button, the odds go into the link after the # sign, a part that a website never receives.