Free Tool · Betting Math

Odds Converter

Convert betting odds between American, decimal, and fractional formats, and see the implied probability.

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Odds Conversion
+100American Odds
2.00Decimal Odds
1/1Fractional Odds
50.0%Implied Prob
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One price, three formats50% implied probability
0%25%50%75%100%50%+1002.001/1
Frequently asked2 questions
How do I convert decimal to American odds?
If decimal ≥ 2.0, American = (decimal − 1) × 100. If decimal < 2.0, American = −100 ÷ (decimal − 1).
What does +150 mean?
American +150 means a $100 stake wins $150 profit. In decimal that is 2.50, or 3/2 fractional, a 40% implied probability.
More free toolsBetting calculators
Parlay Calculator→Combine multiple bets into one parlay and see the combined odds, total payout, and implied probability.Bet Calculator→Enter your odds and stake to see the exact payout, profit, and implied probability of a single bet.Expected Value Calculator→Estimate the expected value of a bet from your win probability and the offered odds.No-Vig Fair Odds Calculator→Remove the sportsbook's margin from a two-way market to get the fair odds and fair probability.Arbitrage Calculator→Check whether two prices form an arbitrage and get the stake split for a positive return on every outcome.Kelly Criterion Calculator→Find the bankroll-optimal stake from your win probability and the odds, with fractional-Kelly options.

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Odds Converter - American, Decimal, Fractional | Courtside