Bookmaker margin
from the line odds
2 outcomes
3 outcomes
Mathematical (overround)
—
sum of probabilities − 100%
Bookmaker's (real)
—
bookmaker's share of the bank
Mathematical margin — by how much the sum of inverse odds exceeds 100% (the classic overround).
Bookmaker margin — the real share the bookmaker keeps when stakes are spread equally across all outcomes (this is usually what bookmakers mean by the line margin; it is always smaller than the overround).
Bookmaker margin — the real share the bookmaker keeps when stakes are spread equally across all outcomes (this is usually what bookmakers mean by the line margin; it is always smaller than the overround).
Stake distribution (arbitrage)
how much to stake on each outcome so the profit is the same
2 outcomes
3 outcomes
System M of N
winnings when outcomes partly match
Odds converter
decimal ⇄ American ⇄ fractional
Enter a value in any field and the other two recalculate automatically.
Stake Distribution Calculator
Stake distribution lets you split an amount across several outcomes so the result is the same whichever outcome happens. If the sum of the inverse odds (1/odds) is below 100%, you get an arbitrage (surebet): the result at these odds is known in advance.
Enter the odds and the total amount: the calculator will show the stake on each outcome and the result. In practice, odds change quickly and bets are not always accepted, so the calculation is for reference only.