Pace Calculator
Distance and time in — pace, speed, and race projections out.
How this is calculated
pace (min/km) = total minutes ÷ km · min/mile = min/km × 1.609 · km/h = 60 ÷ pace
Worked example (the defaults): 5 km in 25:00 is 5:00 per km — 8:03 per mile, 12 km/h. Held flat, that pace delivers a 50:00 10K, a 1:45:29 half, and a 3:30:58 marathon. The projections assume no fade, which for anything beyond your training distance is optimistic by design — see the FAQ.
Common race-pace anchors
| Goal | Pace /km | Pace /mile |
|---|---|---|
| Sub-25 5K | 5:00 | 8:03 |
| Sub-50 10K | 5:00 | 8:03 |
| Sub-2:00 half | 5:41 | 9:09 |
| Sub-4:00 marathon | 5:41 | 9:09 |
| Sub-3:00 marathon | 4:16 | 6:52 |
Frequently asked questions
How is running pace calculated?
Total time ÷ distance. 25 minutes over 5 km = 5:00 per km. The result also shows min/mile (multiply by 1.609) and speed in km/h (60 ÷ pace) — the same run, three dialects.
What are the finish-time projections?
Your pace held perfectly flat across each classic distance — 5K, 10K, half marathon (21.0975 km), marathon (42.195 km). Real racing adds fade: even seasoned runners slow 2–5% in a marathon's back half, so treat long projections as best-case.
What pace do I need for a sub-2-hour half marathon?
5:41 per km (9:09 per mile) — 120 minutes ÷ 21.0975 km. For a 4-hour marathon: 5:41/km as well, conveniently; sub-25 5K needs 5:00/km flat.
Is treadmill pace the same as road pace?
Mechanically close; effort-wise treadmills run slightly easier at the same number (no wind, moving belt). The common adjustment is a 1% incline to approximate road effort. The math on this page is identical either way.