Calculate football Speed Score from body weight and a 40-yard dash time, or reverse the formula for a target time or weight.

Required: player weight and 40-yard dash time.

The published formula uses pounds. Kilograms are converted before calculation.

Football Speed Score Formula

Speed Score is a size-adjusted football testing metric introduced by Bill Barnwell. It combines player weight with 40-yard dash time and gives time a fourth-power effect:

Speed Score = (Weight₍lb) × 200) / (Time₍seconds)⁴)

The formula rewards athletes who maintain fast 40-yard times at higher body weights. It was designed with a reference level near 100, but comparisons should account for position, era, data source, and testing protocol.

Why Time Is Raised to the Fourth Power

The fourth-power term makes the score highly sensitive to small changes in time. A small timing difference can matter much more than the same percentage change in weight. Keep the full measured time during calculation and round only the final display.

Weight Units

The published equation uses pounds. When kilograms are selected, the calculator converts the entered value to pounds using 2.2046226218 pounds per kilogram before applying the formula. Reverse weight mode converts the answer back to the selected display unit.

Solving for a Target Time

To find the 40-yard time associated with a target score at a given weight, the equation is rearranged:

Time = [4](Weight₍lb) × 200) / (Target Score)

This is a mathematical benchmark. It does not estimate whether an athlete can attain that performance.

Solving for a Target Weight

Weight mode shows the formula-equivalent body weight for a selected time and target score:

Weight₍lb) = (Target Score × Time₍seconds)⁴) / (200)

The result is not a recommended playing weight or a reason to gain or lose weight.

Example

A 227 lb player with a 4.37-second 40-yard dash has a Speed Score of approximately 124.5. A 200 lb player at 4.50 seconds has a score of approximately 97.5.

Interpretation and Limitations

  • Speed Score combines only weight and 40-yard time; it does not measure agility, technique, strength, decision-making, durability, or football skill.
  • Hand-timed and electronically timed results should not be mixed without a documented comparison method.
  • Weight and time should come from the same testing period when tracking change.
  • The historical scale is descriptive and does not guarantee a roster, draft, or performance outcome.

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Sources

Bill Barnwell. Combine Stats Not Created Equal. ESPN and Football Outsiders, 2008.

Football Outsiders. Speed Score methodology discussion published by ESPN, 2013.