Enter a point spread, the price on it, and the sport. The calculator returns the de-vigged cover probability, the equivalent moneyline price, the implied win-outright probability, and (for football) the push probability at the spread number.
The relationship between a point spread and a moneyline is governed by the distribution of game margins. For any given spread, the probability of covering it equals the probability that the actual margin lands on the right side of the spread. Sharp markets price the two consistently — when they don't, value exists.
This calculator models each sport's margin distribution as a normal curve centered at the spread, with a sport-specific standard deviation derived from historical results:
The push probability (for whole-number spreads like -3, -7, -10) is empirically estimated — about 8% of NFL games land exactly on -3, 5% on -7, 3% on -10. For half-point spreads (-3.5, -7.5), the push probability is zero.
When a book offers both a spread and a moneyline on the same favorite, the prices should be consistent with each other under the sport's margin distribution. If they're not, one side is offering more value than the other. Sharp bettors who scan both markets find these mispricings — usually the result of asymmetric public action on one market or stale lines.
Pair this with the No-Vig Calculator to strip both prices to their fair-line equivalents, then compare. The difference between de-vigged spread cover probability and de-vigged win-outright probability is where the edge lives.