Estimate a 100 m FAT performance from 10-yard and 40-yard splits, or estimate a 40-yard time from 20 m and 100 m splits, using a split-calibrated acceleration model.
40-Yard Dash to 100m Formula or Method
The estimator fits a mono-exponential horizontal sprint profile to two measured splits, derives acceleration time constant and maximum-velocity parameters, and numerically solves for the requested distance.
How the Calculation Works
The requested output field is hidden, disabled, cleared, and made non-required. Only the source values required for the selected relationship remain available.
How to Use This Calculator
- Select the result you want in the Solve for menu.
- Enter only the visible source values and their explicit units.
- Select Calculate and review the primary answer, supporting values, and substituted steps.
- Use Reset before starting a different performance or scenario.
Worked Example
A 1.55 s 10-yard split and 4.50 s 40-yard time, paired with a 0.15 s reaction assumption, fit τ ≈ 0.6437 s and Vmax ≈ 9.4833 m/s. The estimated 100 m FAT is 11.34 s.
Input and Result Guide
| Item | How to use it |
|---|---|
| 10 yd | 9.144 m exactly. |
| 40 yd | 36.576 m exactly. |
| Reaction time | Added to a gun-relative 100 m estimate and removed from entered FAT splits before fitting. |
| Two splits | Required because one total time cannot separately identify acceleration and maximum velocity. |
| Result | A model estimate, not a timing-system conversion or recruiting guarantee. |
Interpreting the Result
Keep timing method, event distance, units, venue conditions, and scoring rules consistent when comparing results.
Assumptions and Limitations
The profile assumes smooth acceleration and does not model late-race deceleration, surface, footwear, blocks versus a football stance, wind, altitude, or timing-system differences. Incompatible split pairs are rejected rather than forced into a result.
Common Questions
Why did an input disappear when I changed Solve for?
The hidden field is the requested output. Enter the remaining visible values and the calculator will solve for that target.
Will my last successful calculation be restored?
Yes. The calculator saves enabled source values and the successful result in this browser. Reset clears that saved state.
Sources
Healy and colleagues, mono-exponential sprint-profile model, 2022; National Institute of Standards and Technology, exact international yard definition.