Turn a goal time into the even pace to hold, with cumulative splits for 5K, 10K, half and full marathons — or predict a finish time from your pace.
All calculations happen entirely in your browser. Your distance, goal time and pace are never transmitted to any server.
Even pacing is division: convert everything to seconds, divide by the distance you must cover, and you get the pace to hold for every kilometre or mile. The calculator shows that arithmetic in both directions and lays the result onto a cumulative split table.
pace = total time ÷ distancefinish = pace × distancespeed = 3,600 ÷ pace-seconds per unitStraight arithmetic, not coaching advice: 4:00:00 is 14,400 seconds, and the marathon is 42.195 km, so you need 14,400 ÷ 42.195 ≈ 341 seconds per kilometre — 5:41/km, which is 9:09 per mile. Enter 4:00:00 with the Marathon preset and the table shows every 5K checkpoint you must hit to stay on that line.
The math is exact, the model is not. The table assumes a flat course and an even pace, but a climb costs more time than the matching descent gives back, so a hilly marathon runs slower than the even-pace number suggests. Use the splits as a ceiling to check against and plan to slow on the climbs rather than chasing the same watch pace everywhere.
Yes. Switch the km/mi toggle and the distance, presets (5K = 3.11 mi, half = 13.11 mi, full = 26.22 mi), split table and interval column all move to miles, while per-km and per-mile pace are always both shown in the result cards.
Yes — the calculator works with average-pace math. A run/walk plan still has one total time over the whole distance, so enter that finished time (running plus walking plus pauses) and the pace it reports is the average you must sustain, which is exactly what a race clock sees.
No. The whole calculator is a few lines of vanilla JavaScript running in your browser. Your distance, goal time and pace never leave your device — there is no account, no tracking and no network request attached to a calculation.
If you just finished with Running Pace Calculator, the natural next steps are Steps Calculator, One Rep Max Calculator, Ideal Weight Calculator, or browse every tool in Health Tools.