MPH / Speed Calculator
40-yard dash split analysis: velocity, speed, and acceleration for every phase of the sprint.
Split Inputs
Enter each split as a distance in yards and the time it took to cover that distance, for example the 0 to 10 yard segment of a 40 yard dash. The calculator converts each split to velocity and speed, so you can see where an athlete is still accelerating and where they have reached top speed.
This run’s peak speed
20.9mph, 30-40 split
Speed Signature
This profile's biggest gap relative to the rest of the run is power output. That is the one to target first. Each axis is scored against this athlete's own run, or a fixed reference ceiling for top-end speed (25 mph) — this tool has no norms database to compare against other athletes.
Velocity curve
Full split data
| Split | Yards | Seconds | Velocity m/s | Speed mph | % of peak | Pace min/mi | Accel m/s/s |
|---|---|---|---|---|---|---|---|
| 0-10 | 10.0 | 1.80 | 5.08 | 11.36 | 54.4% | 5.28 | 2.82 |
| 10-20 | 10.0 | 1.10 | 8.31 | 18.60 | 89.1% | 3.23 | 2.94 |
| 20-30 | 10.0 | 1.02 | 8.96 | 20.05 | 96.1% | 2.99 | 0.64 |
| 30-40 | 10.0 | 0.98 | 9.33 | 20.87 | 100.0% | 2.87 | 0.37 |
| Total | 40.0 | 4.90 | 7.46 | 16.70 | |||
The markdown download includes the raw data, the Speed Signature scores, and a ready-made prompt for your own AI assistant to interpret the profile. The PDF report opens a print-ready page with the same profile, ready to save as a PDF from your browser's print dialog. Peak power is a field-method estimate most sensitive to first-split timing accuracy, not a lab measurement. All of this is a discussion starter, not a prescription.
Download the build
Want the whole tool, not just a report? These downloads contain the complete source for this calculator: the math, its tests, the component used on this page, and a dependency free standalone version you can open straight in a browser. Feed either one to an LLM to ask questions, extend the tool, or port it to another language.