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Odds payout calculator

Type odds in any format to see the payout and profit for your stake, the implied probability, and the same odds in decimal, fractional and American form. Add up to four more legs for a parlay.

Example: 2.50

Total payout

$25.00

Profit

$15.00

Implied probability
40.0%
Decimal
2.50
Fractional
3/2
American
+150

Payout = stake × decimal odds. Implied probability = 1 ÷ decimal odds.

How the three odds formats work

All three formats describe the same thing, how much you get back for each unit you stake, written in different ways.

FormatExampleWhat it means$10 stake returns
Decimal2.50Total return per 1 staked, stake included$25.00
Fractional3/2Profit of 3 for every 2 staked$25.00
American+150Profit on a 100 stake (minus sign: stake needed to win 100)$25.00
Implied probability40%1 ÷ decimal odds$25.00

The formulas

  • Payout = stake × decimal odds
  • Profit = payout − stake
  • Fractional to decimal = (numerator ÷ denominator) + 1
  • American to decimal = odds ÷ 100 + 1 for positive odds; 100 ÷ |odds| + 1 for negative odds
  • Implied probability = 1 ÷ decimal odds
  • Parlay odds = decimal odds of leg 1 × leg 2 × leg 3 …

Why implied probabilities add up to more than 100%

If a coin flip were priced fairly, both sides would be 2.00 (50% each). Bookmakers offer something like 1.91 on each side instead, which implies 52.4% + 52.4% = 104.8%. The extra 4.8% is the bookmaker's margin, sometimes called the overround or vig. Comparing the implied probability with your own estimate of the real chance is the only way to judge whether odds are good value.

This is a math tool. It doesn't link to or recommend any betting service. If you gamble, only use money you can afford to lose, and check the rules where you live.

Frequently asked questions

How do I calculate a payout from decimal odds?

Multiply your stake by the decimal odds. A $10 stake at 2.50 returns $25: your $10 back plus $15 profit.

How do I convert American odds to decimal?

For positive odds, divide by 100 and add 1 (+150 → 2.50). For negative odds, divide 100 by the number without its minus sign and add 1 (−200 → 1.50).

What does implied probability mean?

It is the chance of the outcome that the odds suggest: 1 divided by the decimal odds. Odds of 2.50 imply 40%. Bookmakers build a margin into their odds, so the implied probabilities of all outcomes add up to more than 100%.

How are parlay (accumulator) odds calculated?

Multiply the decimal odds of every selection. Three legs at 2.50, 1.80 and 2.00 give combined odds of 9.00, so a $10 stake returns $90 if every leg wins.

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