BLAKbets

Sports betting odds converter

Enter odds in any of the three formats. See decimal, American and fractional equivalents, plus implied probability.

Input odds format
Decimal
2,50
American
+150
Fractional
3/2
Probability
40,00%

Pure maths. No sign-in needed. Amounts are in USD, just like the platform.

Let the scanner find your next opportunity

The calculator does the maths. BLAKbets finds the opportunities, with over 143 arbs detected daily, calculated stakes, freshness indicators and direct sportsbook links.

View plans

No trial period. See plans and prices on the homepage. Adults aged 18+ only.

Formula

How odds conversion works

  1. 01

    American → decimal

    Positive: 1 + odds/100. Negative: 1 + 100/|odds|. Decimal 2.00 equals +100.
  2. 02

    Fractional → decimal

    1 + numerator/denominator. 5/2 equals 3.50; 1/2 equals 1.50.
  3. 03

    Decimal → probability

    Implied probability = 1 / decimal odds. 3.50 implies 28.57%.

Example

Example: fractional odds 5/2

Questions

Frequently asked questions

How do I convert American to decimal odds?

Positive odds: 1 + odds / 100, so +150 is 2.50. Negative odds: 1 + 100 / |odds|, so −200 is 1.50.

How do fractional odds work?

The fraction gives net profit per stake: 5/2 means 5 units of profit for 2 staked. Decimal odds are 1 + the fraction, so 5/2 = 3.50.

Which format is easiest for calculations?

Decimal odds show total payout per unit staked. Implied probability is 1 / odds. That's the format used by our board and calculators.

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