Set the assumption
Seconds, M:SS or H:MM:SS; for example, 1110 or 18:30. Blank or malformed clocks clear the answer.
Explore an assumed 0–20% reduction. This range does not describe realistic gains. The native slider moves by 0.1 percentage points; type a more precise value above.
The five original rates are editorial starting points. They are not measured effects for a named shoe, runner or event.
Shoe-time scenario
Illustrative example: 18:30 · 3% assumed time reduction.
Regular → super shoe, under the entered assumption.
- Recorded time
- 18:30
- Recorded minus scenario
- 33.3 seconds
This compares an assumed reduction in time. It does not predict your individual shoe response.
Read the comparison
Scenario = 1,110 seconds × (100 − 3) ÷ 100. Calculated time: 1,076.7 seconds (rounded to 3 decimal places).
The two directions are mathematical inverses before rounding. A 3% reduction in time is not reversed by adding 3%; the reverse divides by 0.97.
Clocks round to whole seconds and carry into minutes and hours. Positive times below half a second and values beyond whole-second precision are labeled. The difference is signed seconds, not a promised gain.
The existing preset rates are not a published prediction formula. Running-economy measurements and race-time changes are different quantities; this tool applies the time percentage you enter directly. Shoe model, runner response, pace and course are not modeled inputs.