About the Betting Odds Converter
Sportsbooks show the same price in different ways: American or moneyline odds such as +150 or −110 in the US, decimal odds such as 2.50 in Europe, Canada and Australia, and fractional odds such as 3/2 in the UK and Ireland. This odds converter translates any one of them into the others and shows the implied probability — the chance of winning the price represents.
Use it to compare prices between books that quote different formats, to check whether a bet offers value against your own estimate of the probability, or simply to understand what a stake would return. Enter a stake to see the profit and the total payout including your stake.
Implied probability here is the raw figure from a single price and includes the bookmaker’s margin (the vig). The fair probabilities of all outcomes in a market add up to 100%; bookmaker prices add up to more.
With the default inputs, the implied probability is 40%. Change any value above to recalculate instantly.
How to use the betting odds converter
- 1Choose the format your odds are in.
- 2Enter the odds — for American odds include the minus sign for favorites.
- 3Enter your stake to see profit and total payout.
- 4Read the equivalent odds in every format and the implied probability.
Formula and method
Decimal odds are the total return per 1 unit staked, so they are the easiest base for converting. Positive American odds show the profit on a 100 stake, and negative American odds show the stake needed to win 100. Fractional odds n/d show profit relative to stake, so decimal = 1 + n/d.
Implied probability is 1 divided by the decimal odds. Profit is stake × (decimal − 1) and the payout adds the stake back. Fractions produced from decimal or American odds are reduced to the nearest fraction with a denominator of 100 or less, which matches how bookmakers quote them (for example −110 becomes 10/11).
- A
- American (moneyline) odds
- n/d
- Fractional odds
- P
- Implied probability
Worked examples
Underdog at +150
+150 means a $100 bet wins $150 profit. That is decimal 2.50 and fractional 3/2, and it implies a 40% chance of winning.
Standard −110 line with a $110 stake
At −110 you stake $110 to win $100. Decimal odds are 1 + 100/110 ≈ 1.909, fractional 10/11, and the implied probability is 52.38% — above 50% because of the bookmaker’s margin.
UK price of 5/1 with a $20 stake
5/1 pays five times the stake in profit, so $20 wins $100 and returns $120. That is decimal 6.00, American +500 and a 16.67% implied chance.
Fair odds for a 25% chance
An outcome with a 25% chance has fair decimal odds of 1 ÷ 0.25 = 4.00, which is +300 American or 3/1 fractional.
Frequently asked questions
How do I convert American odds to decimal?+
For positive odds, divide by 100 and add 1: +250 becomes 3.50. For negative odds, divide 100 by the number (ignoring the sign) and add 1: −200 becomes 1.50.
What does −110 mean in betting?+
It means you must stake $110 to win $100 profit. It is the standard price on point spreads and totals in the US and implies a 52.38% chance, which builds in the sportsbook’s margin.
How do I calculate implied probability?+
Divide 1 by the decimal odds. Decimal 2.00 implies 50%, 1.50 implies 66.7% and 4.00 implies 25%. For American odds, convert to decimal first or use 100 ÷ (A + 100) for positive odds and |A| ÷ (|A| + 100) for negative odds.
What is the vig or overround?+
It is the bookmaker’s margin. Add up the implied probabilities of every outcome in a market; anything over 100% is the overround. Two sides at −110 total 104.76%, a margin of about 4.5%.
What does evens mean?+
Evens (or even money) is 1/1 fractional, 2.00 decimal and +100 American. A winning bet doubles your stake, and the implied probability is 50%.