No-vig calculator
Put in both sides of a line and this strips out the book's margin, so you see the price each side would carry if nobody took a cut. That fair price is the number to measure a bet against.
- Bookmaker’s margin
- 3.5%
- Fair odds, side A
- -138 (58.0%)
- Fair odds, side B
- +138 (42.0%)
What it shows
Take a line of -150 and +130. The two implied chances add up to 103.48 percent, and the extra 3.48 points are the book's. Spread back out, the fair chances are about 58 and 42 percent, a fair price of about -138 and +138. A standard -110 both ways comes out at 50 percent each. A coin flip, with a cut on top.
The mistake people make
They treat the fair price as the right price. I wouldn't. It is only the book's own opinion with the margin removed, and books are wrong more often than their prices let on. Where I find it helps is in comparing, and on a slow afternoon of shopping three or four books for the same game it is the quickest way I know to see which number is out of line: if another book offers better than the fair price on one side, that bet has value against the first book's line. The expected value guide shows how to use it, and the vigorish page explains the cut itself.