A QUICK WALKTHROUGH

How to use this tool

Enter the race distance in kilometers, goal total time in minutes, and tolerance percentage.
Use the target, fast, and slow paces with the kilometer elapsed splits as a planning guide.

Formula and scope

Target pace = goal total minutes ÷ race distance km. Fast pace = target pace × (1 − tolerance ÷ 100). Slow pace = target pace × (1 + tolerance ÷ 100). For each kilometer, elapsed split = pace × kilometer number. The finish-time range uses the fast and slow paces over the full distance.

How to use the band

Use the target pace for the goal and the fast/slow edges to plan a flexible effort. Splits are shown by kilometer and include the total finish range at the two edges.

Guide only

This is a pacing guide, not a guarantee. Terrain, weather, fitness, fatigue, and race conditions can change actual pace and finish time.

Local processing

Inputs are processed in your browser and are not uploaded.

Input bounds and report

Distance must be positive and at most 10,000 km (at most 10,000 table rows); goal minutes positive; tolerance 0% through less than 100%, entered by you. Every whole kilometer below the finish and the finish itself appear in both the HTML table and TXT, including a fractional finish. Use finite decimal inputs with at most 15 significant digits and magnitude at most 9,007,199,254,740,991. Arithmetic that loses a nonzero value or cannot distinguish required terms is rejected. Copy and TXT contain the successful raw/parsed input snapshot, units, formulas and all unrounded browser-number results; editing clears it.

GOOD TO KNOW

Common questions

What does the tolerance percentage mean?

It sets the width of the pace band around the target. A 5% tolerance makes the fast pace 5% quicker and the slow pace 5% slower.

Are the results a race prediction?

No. They are planning estimates based only on the values you enter.