Bet Calculator

Formatting only. This does not change the calculation.
American (+150, -110), decimal (2.50), fractional (3/2) or a probability (40%).
Leave on automatic unless a bare number is ambiguous.
For arbitrage this is the total to spread across all outcomes.
Comma-separated. Parlay legs, arbitrage outcomes or the whole market for a no-vig calculation.
Kelly staking needs your own estimate, not the bookmaker's implied probability.
Multiply full Kelly by this. Half Kelly (0.5) keeps most of the growth with far less variance.
Decimal odds
2.5
Betting Odds Calculator
American / moneyline odds
150
Fractional odds
3/2
Implied probability
40 %
Hong Kong odds
1.5
Indonesian odds
1.5
Malay odds
-0.666667
Profit if the bet wins
150
Total return (stake plus profit)
250
Break-even win probability
40 %
Worked out from Kelly, J.L. Jr (1956), "A New Interpretation of Information Rate", Bell System Technical Journal 35(4), 917-926 and 3 other sources.
This is an arithmetic tool, not betting advice. Bookmaker prices already carry a margin, so the long-run expected value of a bet at posted odds is negative unless you genuinely have an edge. Gamble only what you can afford to lose.

How this is worked out

2 steps
  1. Decimal price = 2.5, i.e. 150 American, 3/2 fractional, 40% implied.
  2. A stake of 100 returns 250 in total, a profit of 150.

Results are general information, not financial, tax, legal, medical or engineering advice.