Bookmaker Margin (Overround)

Bookmakers price markets so the implied probabilities exceed 100%. That gap is the margin (overround).

A fair coin toss would be 2.00 each way. A book might offer 1.91 / 1.91, embedding roughly 5% margin.

Lower margins on popular leagues mean slightly fairer prices — compare odds across books on our tip pages.

Margin makes long-term profit from random picks nearly impossible without genuine value edges.