NFL Cover Probability Calculator

A free tool for determining the cover probability and expected value of a bet based on a projected line and market line

Enter Lines

Enter your projected line and the current market line to calculate cover probability and expected value.

How to use:

  • • True Line: Your projected spread (-30 to 30)
  • • Market Line: Current sportsbook line (-24 to 24)
  • • Positive values = underdog, negative = favorite

Cover Probability & EV

4.79%

Positive EV

Expected value of 4.79% indicates a profitable bet on average if your line is accurate.

Probability Breakdown

Cover
50.00%
Push
8.90%
Loss
41.10%
Cover: 50.00%
Push: 8.90%
Loss: 41.10%

A true 3.5 point favorite has a 50.00% chance to win by more than 3

NFL Cover Probability Calculator - Find Expected Value in Spread Betting

What is Cover Probability?

Cover probability is the likelihood that a team will beat the point spread offered by sportsbooks. In efficient markets, the cover probability for any spread should be approximately 50% after accounting for the vig. However, if you have a different view of the game than the market, you can use this calculator to determine your edge.

For example, if the market has Team A as -7 favorites but your analysis suggests they should be -10 favorites, this calculator will show you the probability that Team A covers -7 based on historical NFL margin of victory patterns.

How the nfelo Cover Probability Model Works

The nfelo cover probability calculator uses a optimization model built on historical NFL spread and margin data. The model analyzes:

  • Historical margin distributions given specific point spreads
  • Key number analysis (3, 7, 10, etc.)
  • And then fits a composite distribution model to generalize the historical patterns to any spread

By examining thousands of historical games, the model can estimate the probability that a team favored by X points will win by Y or more points.

Learn more about the methodology

Understanding Expected Value (EV)

Expected Value is the average amount you can expect to win or lose per bet if you placed the same bet many times. The formula is:

EV = (Probability of Winning × Amount Won) - (Probability of Losing × Amount Lost)

Positive vs Negative EV

  • Positive EV (+EV): You expect to profit long-term
  • Negative EV (-EV): You expect to lose long-term
  • Break-even (0 EV): No expected profit or loss

Most bets at standard -110 odds require 52.38% win probability to break even. If your calculated cover probability exceeds this threshold, you have a positive EV bet. This calculator uses the margin of victory distribution to calculate cover probability, and then derives the expected value by assuming -110 odds.

Real-World Example

Scenario: Chiefs vs Bills

  • Market: Chiefs -3
  • Your projection: Chiefs -5.5
  • Calculator Results:
    • Cover probability: 54.26%
    • Expected value: +11.59%

This edge exists because your model sees the Chiefs as stronger favorites than the market does. If the Chiefs were a "true" -5.5 favorite, then they would be expected to win by more than 3 points 54.26% of the time. This is above the break-even point of 52.38% and results in positive expected value.

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