Running Pace Calculator

Distance, time, and pace in one place

The running pace calculator answers two questions. In pace mode it takes a distance and a finish time and returns your pace per kilometre or mile plus your speed. In time mode it takes a distance and a target pace and returns the finish time.

How each mode works

Distance is entered in kilometres or miles. In pace mode, the time is entered as hours, minutes, and seconds, then converted to total seconds and divided by distance:

Pace = total seconds ÷ distance

Speed is distance divided by hours, shown in both km/h and mph. Pace per mile is the pace per unit multiplied by 1.60934 when the chosen unit is kilometres, reflecting the mile conversion. In time mode, pace is entered as minutes plus seconds, converted to seconds, and multiplied by distance:

Finish time = (pace minutes × 60 + pace seconds) × distance

Worked example with the default inputs

The tool opens in pace mode with 5 km and 30:00.

1. Total seconds = 30 × 60 = 1,800 s
2. Pace = 1,800 ÷ 5 = 360 s = 6:00 per km
3. Speed = 5 ÷ 0.5 h = 10.00 km/h
4. Pace per mile = 360 × 1.60934 = 579 s = 9:39

Switch to time mode with the same 5 km and a pace of 6 minutes: finish time = 6 × 60 × 5 = 1,800 s = 30:00, listed as 1,800 total seconds.

Pace and speed reference

The mile pace is always the km pace multiplied by 1.60934, which is why a 6:00/km pace becomes 9:39/mile rather than anything close to six minutes.

Using pace to plan training

Race pace is the fast end of the range; easy running should sit 60 to 90 seconds per kilometre slower. A common split is roughly 80% of weekly volume at easy pace and 20% at harder efforts. In time mode you can build interval sessions directly: a set of 400 m repeats at a chosen pace gives the exact split time per repeat. Add a small buffer to any race-day prediction, because hills, heat, and fatigue slow the final kilometres.

Common mistakes

• Mixing kilometres and miles. The same effort is a very different number in each unit; state the unit before comparing runs.
• Running every session at race pace. Too much intensity is the most common cause of injury and stalled progress.
• Ignoring the course. A flat-track pace does not transfer directly to a hilly route.
• Mixing up the modes. Pace mode needs a finish time; time mode needs a pace. Entering one where the other belongs produces a nonsensical result.

What is a good running pace?

There is no universal answer; it depends on distance and experience. A beginner might hold 6:30–7:30 per kilometre, while a club runner sits nearer 4:00–4:30. Compare against your own past times rather than someone else’s, and let consistent easy mileage move the number.

How do I convert a 5K time to a 10K estimate?

Doubling a 5K pace overestimates a 10K slightly, because you slow as distance grows. Use the tool to find your 5K pace, then add a few seconds per kilometre when planning a 10K. Treat any prediction as a target to test, not a guarantee.

Why does the tool show speed and pace?

Treadmills and most watches default to speed in km/h, while many runners think in minutes per mile. Showing speed in both km/h and mph, alongside pace per unit and per mile, removes the conversion work from a session you are about to run.

How do I work out interval split times?

Use time mode once per repeat distance. Enter the repeat distance and your target pace, and the finish time is the split to aim for. For example, 0.4 km at a 6:00/km pace is 2:24, so eight 400 m repeats should each land near that time.

Does treadmill distance match outdoor distance?

Broadly, but a treadmill belt is driven rather than moved by you, and most treadmills read a little generously. Use the same machine and setting to compare sessions, and treat the absolute pace as approximate.

For the effort behind a pace, the heart rate zones calculator maps the same easy-to-hard scale to beats per minute, and the TDEE calculator estimates the calories those runs burn. If recovery is the limiter, the sleep cycle calculator helps plan the nights around hard sessions.