Running Pace Calculator
Convert between distance, time, and pace with race presets and per-km/mile splits.
- pace
- running
- split
- marathon
- 5k
- 10k
- half marathon
About Running Pace Calculator
Runners think in three numbers — distance, time, and pace — and any two of them determine the third. "What pace do I need to break four hours in a marathon?" is a time and distance giving a pace. "If I hold 5:30 per kilometre, how long is my 10K?" is a pace and distance giving a time. "If I ran for 45 minutes at 5:15 / km, how far did I go?" is a pace and time giving a distance.
This calculator does all three, with built-in presets for the common race distances (mile, 5K, 10K, half marathon, marathon) and per-kilometre or per-mile split tables so you can see what your watch should read at each marker if you're holding the target pace.
How to use
Pick what you're solving for using the "Solve for" dropdown — Pace, Time, or Distance. The two unknowns become inputs and the answer slot turns into a big highlighted result.
Enter your distance (with the km/mi toggle), your time (as M:SS or H:MM:SS), and your pace (as M:SS per km or per mile). Click any race preset to fill in a standard distance. The splits panel below shows the cumulative time at each kilometre or mile, useful for printing onto a pace band before race day. The "Copy result" button lifts whichever value was the unknown.
Frequently asked questions
What's a good pace for a beginner runner?
There's no single answer — pace depends on age, fitness, terrain, and goals. As reference points: many recreational runners settle around 6:00–7:00 / km (10:00–11:00 / mile) for steady running, beginners may start slower, and competitive 5K runners average under 4:00 / km. The right pace is one you can hold while breathing comfortably enough to speak in short phrases.
How long is a marathon?
42.195 km, or 26.219 miles, by international athletics standard. The half marathon is exactly half that distance — 21.0975 km / 13.109 miles. Other common race distances: 5K (5 km / 3.107 mi), 10K (10 km / 6.214 mi), and the mile (1.609 km).
What pace do I need for a sub-4-hour marathon?
About 5:41 per kilometre (9:09 per mile) — a 4:00:00 marathon time divided by 42.195 km. Enter "Marathon" as the distance preset and 4:00:00 as the time with Solve mode set to Pace, and the calculator confirms the exact pace.
What are race splits?
Splits are cumulative time markers at regular intervals along the race — the elapsed clock reading at each kilometre or mile. Printing them on a pace band lets you check on each marker whether you're on, ahead of, or behind your target pace. The splits panel here shows what each split should read for the pace and distance you've entered.
Does pace differ between roads and treadmills?
Slightly. Treadmills usually let you set a constant pace without wind resistance or course variation, which is fractionally easier than the same pace on a flat road; many runners set a treadmill incline of 1% to compensate. Outdoor pace is also affected by hills, surface, and weather — race conditions are rarely as consistent as a calibrated treadmill.