Do I need to install anything?

No. It runs in any modern browser, free, with no account required.

For Hobbyists & Makers · Marathon Pacing

Marathon Pacing for a tennis serve

Built for hobbyists & makers exploring it for fun. Play with real physics and math, no license and no setup — just open and tinker. Simulate a tennis serve live below — adjust the inputs and watch it respond, right in your browser.

Marathon PacingLive

hit your goal time

Controls

Presets

Target time (min)

Race pace is simply your goal time divided by the distance, but how you distribute it matters. A negative split — starting conservatively and finishing faster — is how nearly every marathon world record is run, because going out too hard burns glycogen and invites the dreaded wall. Even pacing is the safe default.

▶ Run in Python

Data Inspector

Average pace5:41/km

Speed10.6 km/h

Finish time4h 0m

Governing equation

pace = \frac{T}{d} = \frac{240 min}{42.2 km} = 5.69 min/km

Reading this result: Even pacing holds 5:41/km the whole way — the safe default, since pace is simply goal time (240 min) divided by distance (42.2 km).

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Frequently asked questions

Is this good for hobbyists & makers?: Yes — this version of "Marathon Pacing for a tennis serve" is framed for hobbyists & makers exploring it for fun. Play with real physics and math, no license and no setup — just open and tinker.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.