Odds Calculator

Convert between probability and decimal betting odds.

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Direction

Probability (%)

Decimal odds

Result

Enter values to calculate.

Summary

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Detail

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Convert between probability and decimal betting odds.

How It Works

How Odds Calculator Works

Decimal odds are simply the reciprocal of the implied probability — a lower probability of an outcome happening corresponds to higher decimal odds, since a rarer event pays out more if it does occur.

Real-World Use Cases

Who Uses Odds Calculator and Why

Converting a probability estimate into decimal betting odds to compare against odds offered elsewhere.
Working out what probability a bookmaker's decimal odds imply for a given outcome.
Converting between probability and odds formats when comparing multiple bets or wagers side by side.

Common Mistakes

Mistakes to Avoid

Assuming decimal odds directly equal the probability — decimal odds are the reciprocal-style relationship of implied probability (the calculator handles the conversion), not the probability value itself.
Assuming bookmaker odds reflect the exact true probability of an outcome — real bookmaker odds are adjusted to include a built-in margin (the "overround"), so implied probabilities across an entire market typically add up to a bit more than 100%.
Comparing decimal odds for two different outcomes without converting both to the same format (probability or odds) first — mixing formats makes for an unreliable comparison.

Pro Tips

Tips for Best Results

Remember decimal odds represent your TOTAL payout per 1 unit wagered, including your original stake — odds of 4.00 mean a winning $1 bet returns $4 total.
To sanity-check a set of bookmaker odds across a whole market, convert each outcome to implied probability and see how far the total exceeds 100% — that excess is the bookmaker's overround.

Troubleshooting

Fixing Common Problems

The implied probabilities from a full set of bookmaker odds add up to more than 100%. — This is expected, not an error — bookmakers build in a margin (the overround) across their odds, which makes the sum of implied probabilities across all outcomes in a market exceed 100% by design.

Glossary

Terms Explained

Decimal odds: A betting odds format representing the total payout (including the original stake) per 1 unit wagered.

Overround: The built-in margin bookmakers add to odds, causing the implied probabilities of all outcomes in a market to sum to slightly more than 100%.

FAQ

Frequently Asked Questions

What do decimal odds actually represent?

Decimal odds show the total payout (including your original stake) for every 1 unit wagered — odds of 4.00 mean a winning $1 bet returns $4 total, implying the bookmaker's assessed probability of that outcome is 25%.

Do bookmaker odds reflect true probability exactly?

Not quite — real bookmaker odds are adjusted to include a built-in margin (the "overround"), so the implied probabilities across all outcomes in a market typically add up to slightly more than 100%.