Point Spread Betting Calculator
Spread to moneyline and implied probability.
How to Use This Calculator
- Enter the point spread (e.g. -3.5 for a 3.5-point favorite)
- Enter the juice/vig (default -110)
- Read the implied win probability and equivalent moneyline for each side
Formula
Implied Probability from Juice:
- For negative odds: Probability = |Odds| / (|Odds| + 100)
- For positive odds: Probability = 100 / (Odds + 100)
Spread to Moneyline (approximation):
- Each point of spread ≈ 2.75% shift from 50/50
Probability to American Moneyline:
- If prob ≥ 50%: Moneyline = -100 × prob / (1 - prob)
- If prob < 50%: Moneyline = +100 × (1 - prob) / prob
Frequently Asked Questions
Point spread — what is it?
A point spread is a handicap loaded onto the favored team to balance the betting. A team at -3.5 must win by 4 or more for the bet to land. The underdog at +3.5 cashes by winning outright or losing by 3 or fewer.
Converting a spread to a moneyline?
Each spread point corresponds to roughly 2.75% of win probability. A -3.5 spread implies about 59.6% win probability, converting to roughly a -148 moneyline for the favorite.
Juice or vig — what is it?
Juice (vig) is the sportsbook’s commission. Standard juice is -110 per side, meaning a $110 bet to win $100. This embedded margin secures sportsbook profit regardless of outcome.
Is the conversion exact?
The spread-to-moneyline conversion is an approximation. The precise relationship varies by sport, specific matchup, and market conditions. It serves best as a quick reference for NFL and NBA betting.