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.
M-of-N Betting System Calculator
An M-of-N system is a set of parlays: from N selected events, all possible combinations of M events are made. For example, a 2-of-3 system consists of three doubles. If only some of the picks win, a payout is possible even when not all of the events come in.
The calculator shows the number of combinations, the stake on each one, and the winnings for different numbers of correct picks. The system reduces the risk of losing everything but does not guarantee a profit.