Betting Odds Converter July 2026

Short answer: Enter decimal, American or fractional odds, or a raw implied probability. The calculator instantly shows the equivalent values in all four fields. Changing any one input recalculates the others.

This tool converts the price format only. It does not decide whether a bet has value, remove bookmaker margin or calculate a stake-specific payout.

How to use the odds converter

1. Click the format you already have.
2. Enter decimal odds such as 2.50, American odds such as +150 or -200, fractional odds such as 3/2, or a percentage such as 40.
3. Read the equivalent values in the result cards.
4. Check the source price again before placing a bet because the market can move.

The converter accepts one active input at a time. Decimal odds must be greater than 1.00, and raw implied probability must be above 0 and below 100 percent.

Common odds conversion examples

These are mathematical equivalents before any market-level margin adjustment. The percentage describes what one price implies in isolation.

Decimal odds conversion formulas

Decimal odds include the returned stake. To convert a decimal price above 2.00 to positive American odds:

American odds = (decimal odds - 1) x 100

For decimal odds below 2.00:

American odds = -100 / (decimal odds - 1)

To convert decimal odds to a fractional numerator-to-denominator ratio, start with:

Fractional value = decimal odds - 1

The converter reduces that value to a practical fraction. Some decimal prices do not map to a short exact fraction, so the displayed fraction can be an approximation.

American odds conversion formulas

Positive American odds show the profit on a 100 stake. Convert them to decimal with:

Decimal odds = 1 + American odds / 100

Negative American odds show the stake needed for 100 profit. Convert them with:

Decimal odds = 1 + 100 / absolute American odds

For example, +150 becomes 2.50. American odds of -200 become 1.50.

Fractional odds conversion formula

Fractional odds show potential profit relative to the stake. For a fraction A/B:

Decimal odds = A / B + 1

Fractional odds of 3/2 therefore become 2.50. Fractional odds of 1/2 become 1.50. The calculator requires a valid numerator and denominator separated by a slash.

How implied probability is calculated

For decimal odds:

Raw implied probability = 100 / decimal odds

Decimal odds of 2.50 imply 40 percent, while 1.50 implies 66.67 percent. This is a raw price conversion, not an estimate of the true chance.

When every price in a bookmaker market is converted and added, the result often exceeds 100 percent because the prices contain overround. Use the vig calculator to inspect a complete market and see a proportionally normalized baseline.

Does the converter calculate payout?

No. The tool has no stake field, so it cannot display a personal payout. For an ordinary cash bet:

Gross return = stake x decimal odds

Profit = gross return - stake

A 20 cash stake at decimal odds of 2.50 has a modeled gross return of 50 and profit of 30 before fees. Free bets, each-way bets, exchange commission and promotional rules require different calculations. Use the betting ROI calculator to measure return across completed bets.

Can converted odds reveal value?

No. Equivalent formats describe the same price. Converting 2.50 to +150 or 3/2 does not change its expected value.

Assessing value requires an independent probability estimate, the exact market and settlement rules, and the final accepted price. Raw implied probability can be a useful comparison, but it still contains any margin built into the price.

Rounding and display differences

American odds are normally displayed as whole numbers, and practical fractional odds use reduced ratios. A converted price can therefore round slightly differently from the original decimal input. Converting the rounded display back again may not reproduce every decimal place.

Use the original quoted price when calculating a stake or comparing markets. Treat converted values as format equivalents, not as a replacement for the accepted bet receipt.

Common odds format mistakes

• Leaving the negative sign off an American favourite.
• Entering a decimal return as if it were fractional profit.
• Using 100 percent, which would imply decimal odds of exactly 1.00 and is not accepted by this tool.
• Calling raw implied probability the true probability.
• Assuming a format conversion removes margin.
• Using rounded converted odds instead of the actual price on the betting slip.

Responsible use

Odds conversion does not make a bet safer or more likely to win. Set a fixed budget, use only money you can afford to lose and never increase a stake because one format makes a return look larger.

If gambling affects bills, sleep, work or relationships, stop and use time-out or self-exclusion tools. Our responsible gambling policy lists practical checks and support routes.