Convert Any Betting Odds Format, Then Check the Margin
Odds are not hard. They are written six different ways, and the sign in front of the number is where people go wrong.
Type a betting price in any format and this odds converter shows the other five, plus the chance the price implies: 1 divided by the decimal odds. A prediction market price works the same way, so 35 cents is a 35% chance and 2.857 in decimal odds. The prices a bookmaker offers on every outcome of one market imply chances that add up to more than 100%, and the excess is the margin: 1.91 and 1.95 give 103.64%, a margin of 3.64 points.
Type a price, read the other five
The tool opens on 2.50, a 40% chance, and, in the margin check, the two prices 1.91 and 1.95. Type your own over them. The conversion table further down lists 89 common prices, from 1.01 to 1001.
Odds converter
Convert a price between six formats, turn a probability or a prediction market price into odds, and measure the margin in a market. Everything is worked out in your browser and nothing is sent anywhere.
Convert one price
Choose the format you have, type the price and read the same price in every format. Type fractions as 5/2, 5-2 or 5:2, and give American odds their sign, such as +150 or -200.
Probability or market price to odds
A chance and a prediction market price say the same thing in different units. Fill in either box, or both: each one gives its own decimal odds.
A price of 40 cents on a market that pays 1 unit is a 40% implied chance.
Margin check
Type the decimal odds of every outcome in one market, taken from one source at one moment. Leave outcome 3 empty for a market with two outcomes.
Proportional method: each implied probability is divided by the booksum, so likelier outcomes lose more points. Other methods spread the margin differently.
Decimal to fractional odds, and back
A fraction n/m is 1 + n/m in decimal odds, and decimal odds d give a fraction equal to d - 1. So 1.80 is 0.80, which is 4/5, and 3.25 is 2.25, which is 9/4. Going back, 9/4 is 1 + 2.25, which is 3.25.
Two spellings, one small gap. The exact fraction of 1.91 is 91/100. The one you will see written is 10/11, which is 1.909, a gap of about 0.02 of a percentage point in implied probability.
American, Hong Kong, Malay and Indonesian
- Decimal: what comes back per unit staked, stake included.
- Fractional: profit over stake.
- American: positive from decimal 2.00 up, negative below. Plus is the profit on 100, minus the stake that wins 100. No figure sits between -99 and +99.
- Hong Kong: decimal minus 1, the profit on a stake of 1.
- Malay: the Hong Kong figure up to evens (decimal 2.00, Hong Kong 1.00), then minus 1 divided by it. Minus means the stake that wins 1.
- Indonesian: the mirror of Malay. The Hong Kong figure from evens up, minus 1 divided by it below.
Take 3.25 and read it off every scale: it returns 3.25 on a stake of 1, wins 9 on every 4, wins 2.25 on 1 in Hong Kong terms, wins 225 on 100 in American terms, takes a stake of 0.444 to win 1 in Malay terms and reads 2.25 again in Indonesian.
At 2.00 the conventions meet: American reads +100 (-100 means the same price), Malay and Indonesian read 1.00. One trap: a -0.25 beside a team name in a handicap market is the line, not a Malay price, and the Asian handicap guide explains those lines.
American is rounded to a whole number, the rest to three decimals at most, so a rounded figure typed back lands near the original: -0.444 returns 3.252, not 3.25.
Which Asian bookmakers a broker account opens is on the betting brokers page.
Implied probability and the margin
Signs sorted. Next, the cost already inside the price.
Implied probability is the chance a price asks you to believe: 1 divided by the decimal odds. In a three-way market, 2.10 implies 47.62%, 3.40 implies 29.41% and 3.60 implies 27.78%. Exactly one outcome happens, so the chances should total 100%. These total 104.81%, the booksum, and the 4.81 points above 100 are the margin.
The margin taken out of 2.10, 3.40 and 3.60
Divide each chance by the booksum: 45.43%, 28.06% and 26.50%, which total 100% before rounding. Turn them back into odds: 2.201, 3.563 and 3.773, each the original price multiplied by the booksum.
That is one method, proportional. Others spread the margin differently, so read the result as what this method gives, not a verdict on who will win. The margin belongs to the prices you typed in, not to any platform. Prices from different sources can total under 100%, the arithmetic behind the arbitrage guide. Whether a price is open to your stake is a separate question, and betting without limits covers who caps your stake.
Prices in cents
Forget bookmakers for a paragraph. A prediction market contract pays 1 unit if an outcome happens, and its price in cents is what you pay for it. At 35 cents you put up 35 cents to get 100 cents back, a profit of 65. That is 1.857 in Hong Kong terms. The same 35 is the chance, 35 out of 100, and 100 divided by 35 is the decimal price, 2.857. The conversion ignores fees and the gap between buying and selling prices, so read it as what a price implies, not what you would keep. Prediction markets have a page of their own.
Implied probability at common prices
Bars are drawn against 100%. Every price in the conversion table further down has its chance in the last column.
Show the data table
| Decimal price | Implied chance |
|---|---|
| 1.25 | 80.00% |
| 1.50 | 66.67% |
| 1.80 | 55.56% |
| 2.20 | 45.45% |
| 3.25 | 30.77% |
| 5.00 | 20.00% |
| 8.00 | 12.50% |
Short prices pack more chance into a small stretch of price. From 1.25 to 1.50 the price moves 0.25 and the chance 13.33 points; from 5.00 to 8.00 it moves 3.00 and the chance 7.50 points.
Odds conversion table, 1.01 to 1001
This table lists 89 common decimal prices from 1.01 to 1001, each in the six formats with the chance it implies. Every row is the converter's own output, so a price typed above returns the same figures. A price that is not listed goes through the tool.
| Decimal | Fractional | American | Hong Kong | Malay | Indonesian | Implied chance |
|---|---|---|---|---|---|---|
| 1.01 | 1/100 | -10000 | 0.01 | 0.01 | -100.00 | 99.01% |
| 1.02 | 1/50 | -5000 | 0.02 | 0.02 | -50.00 | 98.04% |
| 1.03 | 3/100 | -3333 | 0.03 | 0.03 | -33.333 | 97.09% |
| 1.04 | 1/25 | -2500 | 0.04 | 0.04 | -25.00 | 96.15% |
| 1.05 | 1/20 | -2000 | 0.05 | 0.05 | -20.00 | 95.24% |
| 1.06 | 3/50 | -1667 | 0.06 | 0.06 | -16.667 | 94.34% |
| 1.07 | 7/100 | -1429 | 0.07 | 0.07 | -14.286 | 93.46% |
| 1.08 | 2/25 | -1250 | 0.08 | 0.08 | -12.50 | 92.59% |
| 1.09 | 9/100 | -1111 | 0.09 | 0.09 | -11.111 | 91.74% |
| 1.10 | 1/10 | -1000 | 0.10 | 0.10 | -10.00 | 90.91% |
| 1.11 | 11/100 | -909 | 0.11 | 0.11 | -9.091 | 90.09% |
| 1.12 | 3/25 | -833 | 0.12 | 0.12 | -8.333 | 89.29% |
| 1.13 | 13/100 | -769 | 0.13 | 0.13 | -7.692 | 88.50% |
| 1.14 | 7/50 | -714 | 0.14 | 0.14 | -7.143 | 87.72% |
| 1.15 | 3/20 | -667 | 0.15 | 0.15 | -6.667 | 86.96% |
| 1.16 | 4/25 | -625 | 0.16 | 0.16 | -6.25 | 86.21% |
| 1.17 | 17/100 | -588 | 0.17 | 0.17 | -5.882 | 85.47% |
| 1.18 | 9/50 | -556 | 0.18 | 0.18 | -5.556 | 84.75% |
| 1.19 | 19/100 | -526 | 0.19 | 0.19 | -5.263 | 84.03% |
| 1.20 | 1/5 | -500 | 0.20 | 0.20 | -5.00 | 83.33% |
| 1.25 | 1/4 | -400 | 0.25 | 0.25 | -4.00 | 80.00% |
| 1.30 | 3/10 | -333 | 0.30 | 0.30 | -3.333 | 76.92% |
| 1.35 | 7/20 | -286 | 0.35 | 0.35 | -2.857 | 74.07% |
| 1.40 | 2/5 | -250 | 0.40 | 0.40 | -2.50 | 71.43% |
| 1.45 | 9/20 | -222 | 0.45 | 0.45 | -2.222 | 68.97% |
| 1.50 | 1/2 | -200 | 0.50 | 0.50 | -2.00 | 66.67% |
| 1.55 | 11/20 | -182 | 0.55 | 0.55 | -1.818 | 64.52% |
| 1.60 | 3/5 | -167 | 0.60 | 0.60 | -1.667 | 62.50% |
| 1.65 | 13/20 | -154 | 0.65 | 0.65 | -1.538 | 60.61% |
| 1.70 | 7/10 | -143 | 0.70 | 0.70 | -1.429 | 58.82% |
| 1.75 | 3/4 | -133 | 0.75 | 0.75 | -1.333 | 57.14% |
| 1.80 | 4/5 | -125 | 0.80 | 0.80 | -1.25 | 55.56% |
| 1.85 | 17/20 | -118 | 0.85 | 0.85 | -1.176 | 54.05% |
| 1.90 | 9/10 | -111 | 0.90 | 0.90 | -1.111 | 52.63% |
| 1.91 | 91/100 | -110 | 0.91 | 0.91 | -1.099 | 52.36% |
| 1.95 | 19/20 | -105 | 0.95 | 0.95 | -1.053 | 51.28% |
| 2.00 | 1/1 | +100 | 1.00 | 1.00 | 1.00 | 50.00% |
| 2.10 | 11/10 | +110 | 1.10 | -0.909 | 1.10 | 47.62% |
| 2.20 | 6/5 | +120 | 1.20 | -0.833 | 1.20 | 45.45% |
| 2.30 | 13/10 | +130 | 1.30 | -0.769 | 1.30 | 43.48% |
| 2.40 | 7/5 | +140 | 1.40 | -0.714 | 1.40 | 41.67% |
| 2.50 | 3/2 | +150 | 1.50 | -0.667 | 1.50 | 40.00% |
| 2.60 | 8/5 | +160 | 1.60 | -0.625 | 1.60 | 38.46% |
| 2.70 | 17/10 | +170 | 1.70 | -0.588 | 1.70 | 37.04% |
| 2.80 | 9/5 | +180 | 1.80 | -0.556 | 1.80 | 35.71% |
| 2.90 | 19/10 | +190 | 1.90 | -0.526 | 1.90 | 34.48% |
| 3.00 | 2/1 | +200 | 2.00 | -0.50 | 2.00 | 33.33% |
| 3.25 | 9/4 | +225 | 2.25 | -0.444 | 2.25 | 30.77% |
| 3.40 | 12/5 | +240 | 2.40 | -0.417 | 2.40 | 29.41% |
| 3.50 | 5/2 | +250 | 2.50 | -0.40 | 2.50 | 28.57% |
| 3.60 | 13/5 | +260 | 2.60 | -0.385 | 2.60 | 27.78% |
| 3.75 | 11/4 | +275 | 2.75 | -0.364 | 2.75 | 26.67% |
| 4.00 | 3/1 | +300 | 3.00 | -0.333 | 3.00 | 25.00% |
| 4.50 | 7/2 | +350 | 3.50 | -0.286 | 3.50 | 22.22% |
| 5.00 | 4/1 | +400 | 4.00 | -0.25 | 4.00 | 20.00% |
| 5.50 | 9/2 | +450 | 4.50 | -0.222 | 4.50 | 18.18% |
| 6.00 | 5/1 | +500 | 5.00 | -0.20 | 5.00 | 16.67% |
| 6.50 | 11/2 | +550 | 5.50 | -0.182 | 5.50 | 15.38% |
| 7.00 | 6/1 | +600 | 6.00 | -0.167 | 6.00 | 14.29% |
| 7.50 | 13/2 | +650 | 6.50 | -0.154 | 6.50 | 13.33% |
| 8.00 | 7/1 | +700 | 7.00 | -0.143 | 7.00 | 12.50% |
| 8.50 | 15/2 | +750 | 7.50 | -0.133 | 7.50 | 11.76% |
| 9.00 | 8/1 | +800 | 8.00 | -0.125 | 8.00 | 11.11% |
| 9.50 | 17/2 | +850 | 8.50 | -0.118 | 8.50 | 10.53% |
| 10.00 | 9/1 | +900 | 9.00 | -0.111 | 9.00 | 10.00% |
| 11.00 | 10/1 | +1000 | 10.00 | -0.10 | 10.00 | 9.09% |
| 12.00 | 11/1 | +1100 | 11.00 | -0.091 | 11.00 | 8.33% |
| 13.00 | 12/1 | +1200 | 12.00 | -0.083 | 12.00 | 7.69% |
| 14.00 | 13/1 | +1300 | 13.00 | -0.077 | 13.00 | 7.14% |
| 15.00 | 14/1 | +1400 | 14.00 | -0.071 | 14.00 | 6.67% |
| 16.00 | 15/1 | +1500 | 15.00 | -0.067 | 15.00 | 6.25% |
| 17.00 | 16/1 | +1600 | 16.00 | -0.063 | 16.00 | 5.88% |
| 18.00 | 17/1 | +1700 | 17.00 | -0.059 | 17.00 | 5.56% |
| 19.00 | 18/1 | +1800 | 18.00 | -0.056 | 18.00 | 5.26% |
| 20.00 | 19/1 | +1900 | 19.00 | -0.053 | 19.00 | 5.00% |
| 21.00 | 20/1 | +2000 | 20.00 | -0.05 | 20.00 | 4.76% |
| 26.00 | 25/1 | +2500 | 25.00 | -0.04 | 25.00 | 3.85% |
| 34.00 | 33/1 | +3300 | 33.00 | -0.03 | 33.00 | 2.94% |
| 41.00 | 40/1 | +4000 | 40.00 | -0.025 | 40.00 | 2.44% |
| 51.00 | 50/1 | +5000 | 50.00 | -0.02 | 50.00 | 1.96% |
| 67.00 | 66/1 | +6600 | 66.00 | -0.015 | 66.00 | 1.49% |
| 81.00 | 80/1 | +8000 | 80.00 | -0.013 | 80.00 | 1.23% |
| 101.00 | 100/1 | +10000 | 100.00 | -0.01 | 100.00 | 0.99% |
| 126.00 | 125/1 | +12500 | 125.00 | -0.008 | 125.00 | 0.79% |
| 151.00 | 150/1 | +15000 | 150.00 | -0.007 | 150.00 | 0.66% |
| 201.00 | 200/1 | +20000 | 200.00 | -0.005 | 200.00 | 0.50% |
| 251.00 | 250/1 | +25000 | 250.00 | -0.004 | 250.00 | 0.40% |
| 501.00 | 500/1 | +50000 | 500.00 | -0.002 | 500.00 | 0.20% |
| 1001.00 | 1000/1 | +100000 | 1000.00 | -0.001 | 1000.00 | 0.10% |
The highlighted row, 2.00, is where the signs turn. Below it American and Indonesian are negative and Malay is positive; above it American and Indonesian are positive and Malay is negative.
Fractions are exact for every price here. The last column is 100 divided by the decimal price, so it falls as the price rises, from 99.01% at 1.01 to 0.10% at 1001.
Where these sums lead
To weigh a price against your own estimate of the chance, the expected value guide does the sum. If the sums are for an exchange, the Orbit Exchange overview shows what it is. Getting an account is the next question: the routes into Orbit Exchange, comparing brokers and opening the account answer it in that order. Back to the start: the home page.
Converting a price does not improve it
9/4, +225 and 3.25 are one price, and no format improves it. On an exchange, commission comes off the profit of a winning back, so the face price overstates what it pays, and this converter has no commission field. The commission example in the exchange betting guide works the sum, the commission calculator lets you set the rate, pairing a back with a lay shows what a second position does to it and comparing prices across places sets one price against the others.