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Running Pace Calculator

Enter the time and distance of a run to get your pace per km and per mile, your speed, and projected times for standard race distances.

Time

Pace, speed, and race times

Pace is how long it takes to cover one unit of distance — lower is faster. Speed is the distance covered per hour — higher is faster. They are two views of the same thing: a 5:00 / km pace is exactly 12 km/h.

The race-time rows assume you hold your entered pace for the whole distance. That is realistic for distances close to what you ran and increasingly generous as the gap grows, because everyone slows down over longer races. For a marathon prediction from a short run, add a few percent.

Worked example

You run 5 km in 25:00. Pace = 1,500 s ÷ 5 km = 300 s/km =5:00 per km, which is 5:00 × 1.609 ≈8:03 per mile, and a speed of 60 ÷ 5 =12 km/h (7.5 mph). At that even pace a 10K would take 50:00 and a half marathon about 1:45:30 — realistic for the 10K, a stretch for the half.

Pace ↔ speed reference

Pace /kmPace /milekm/hmph
4:006:2615.09.3
5:008:0312.07.5
6:009:3910.06.2
7:0011:168.65.3

Training paces from a race pace

As a rough guide, easy runs sit about 60–90 s/km slower than 5K race pace, tempo runs about 20–30 s/km slower, and interval work at or faster than race pace. Keep most weekly mileage easy and add one or two hard sessions.

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Frequently asked questions

How is pace calculated?
Pace is time divided by distance. Run 5 km in 25 minutes and your pace is 25 ÷ 5 = 5 minutes per kilometre. Multiply by 1.609 to convert a per-km pace to per-mile.
What is a good 5K pace?
It depends entirely on age, sex, and training. As a rough guide, many recreational runners finish a 5K between 25 and 35 minutes (roughly 5:00 to 7:00 per km). Elite times are under 14 minutes.
Are the race predictions accurate?
They assume you hold the same pace over the longer distance, which almost nobody does — pace naturally slows as distance grows. Treat the marathon projection from a 5K time as optimistic; a dedicated race-prediction model (like Riegel's) applies a slowdown factor.
Should I train at my race pace?
Only some of the time. Most training volume should be easy, well below race pace, with focused sessions at or faster than race pace. Running everything at race pace is a common way to plateau or get injured. A rough split for many plans is 80% easy, 20% moderate-to-hard.
How do I convert pace between km and miles?
Multiply a per-kilometre pace by 1.609 to get per-mile (a 5:00/km pace is about 8:03/mile). Divide a per-mile pace by 1.609 to go the other way. Speed in km/h is 60 divided by your pace in minutes-per-km.
What is a realistic pace for my first race?
For a first 5K, most people finish somewhere between 25 and 40 minutes (5:00 to 8:00 per km). Aim to run the first half a touch slower than you think you can, then speed up if you feel good — going out too fast is the most common beginner mistake.
Why can't I hold my 5K pace for a marathon?
Aerobic endurance, glycogen stores, muscle fatigue and heat all degrade pace as distance grows. Prediction models like Riegel's estimate that each doubling of distance slows you by roughly 5 to 7 percent. The race-time rows here assume an even pace, so treat the longer projections as optimistic best cases.

Last reviewed: September 2026. Figures and formulas are checked against their published sources; see the site's data notes.