Odds Calculator
Calculate odds: convert American, decimal and fractional odds, find implied probability and calculate parlay payouts.
Implied probability: 40.0%
American
+150
Decimal
2.50
Fractional
3/2
$100 bet payout
Win $150.00 profit on a $100 bet
Total return: $250.00
Break-even win rate
40.0%
You need to win 40.0% of the time to break even at these odds.
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+150 in decimal and implied probability
+150 is 2.50 in decimal odds: 150/100 + 1. The implied probability is 100 ÷ (150 + 100) = 40.0%. A $100 stake returns $250.00 if it wins, which is $150.00 profit plus your stake back.
-200 in decimal and implied probability
-200 is 1.50 in decimal odds: 100/200 + 1. The implied probability is 200 ÷ (200 + 100) = 66.7%. You risk $200 to win $100, so a $200 stake returns $300.00.
5/2 fractional to American
5/2 means $5.00 profit for every $2.00 staked. In decimal that is 5 ÷ 2 + 1 = 3.50, which is +250 in American odds (a decimal price of 2.00 or more converts to +(decimal − 1) × 100). The implied probability is 28.6%.
3-leg parlay payout example
A $100.00 parlay on -110, +150, -200 multiplies the decimal odds: 1.91 × 2.50 × 1.50 = 7.159. The payout is $715.91 ($615.91 profit). Multiplying the legs' implied probabilities gives 14.0% for all three to win, which is why parlays pay more but win far less often.
Helpful answers
Frequently asked questions
- How do you calculate implied probability from American odds?
- For positive odds, probability = 100 ÷ (odds + 100): +150 is 40.0%. For negative odds, probability = |odds| ÷ (|odds| + 100): -200 is 66.7%.
- How do I convert decimal to American odds?
- If the decimal odds are 2.00 or higher, American = (decimal − 1) × 100, so 3.50 is +250. Below 2.00, American = −100 ÷ (decimal − 1), so 1.50 is -200.
- How is a parlay payout calculated?
- Convert every leg to decimal odds, multiply them together, and multiply by your stake. For $100.00 on -110, +150, -200 the combined decimal odds are 7.159, so the payout is $715.91.
- What is the vig?
- The vig (or juice) is the bookmaker's margin. Add the implied probabilities of both sides of a market and subtract 100%: a -110 / -110 market implies 104.8% combined, so the vig is 4.8%.
For information and entertainment; gambling involves risk.
When to use this
You have a price in one odds format and need it in another right now. Or you are building a parlay and want to know the real payout before placing it. Maybe you are comparing market prices across books and need to translate everything into implied probability so you can see whether the bet has value. This calculator handles those conversions fast, in one place, without switching between separate tools.
It is also useful for bankroll discipline. Betting odds are easy to read incorrectly when you stay inside the sports-betting UI all day. Converting everything into probability makes the tradeoff clearer: what win rate do you actually need to break even, and what does a given price imply about the market's view of the game?
The parlay and payout views solve the two practical questions people ask most often: "What does this ticket return if it wins?" and "How quickly does the probability collapse as I add more legs?" Those numbers matter more than the excitement of stacking prices.
Odds formats explained
American odds show how much you win on a $100 stake when the number is positive, or how much you need to risk to win $100 when the number is negative. +150 means $100 returns $250 total. -200 means you risk $200 to profit $100.
Decimal odds are the cleanest format for multiplication. They show total return per $1 staked, including your stake back. A 2.50 price means a $100 wager returns $250 total.
Fractional odds express profit relative to stake. 3/2 means you win $3 for every $2 risked. They are common in UK and horse-racing contexts and convert directly to decimal by adding 1 after dividing the fraction.
Implied probability and vig basics
Every odds price encodes an implied probability. Decimal 2.00 equals 50.0%. Decimal 1.50 equals 66.7%. American +150 implies 40.0%, while -200 implies 66.7%.
The bookmaker's edge appears when both sides of a market add up to more than 100%. A -110 / -110 market implies about 104.8% combined probability, which means the vig is roughly 4.8%. Removing that margin shows the fair no-vig probability split.
This is why probability is the best comparison layer. Once every price is translated into percentage terms, you can compare books, evaluate parlays, and decide whether the market is worth the risk.
Quick Reference
| American | Decimal | Fractional | Implied Probability |
|---|---|---|---|
| -200 | 1.50 | 1/2 | 66.7% |
| -110 | 1.91 | 10/11 | 52.4% |
| +100 | 2.00 | 1/1 | 50.0% |
| +150 | 2.50 | 3/2 | 40.0% |
| +300 | 4.00 | 3/1 | 25.0% |