About this calculator
Pace — minutes per mile or kilometer — is the runner's native unit. It tells you instantly whether you are on target mid-race, how to set a treadmill, and what a training run means for race day. This calculator converts any distance-and-time pair into both pace units and speed, then projects the same pace across the standard race distances.
One honest caveat: holding a pace gets harder as distance grows. A 5K pace cannot simply be extended to a marathon — endurance, fueling and heat all tax longer efforts. Predictions from a recent race at a similar distance are fairly reliable; predictions that jump two distance classes (10K to marathon) are best-case estimates.
How to use it
- Enter the distance you ran (or plan to run) and choose kilometers or miles.
- Enter the finish time in hours, minutes and seconds.
- Read your pace per km and per mile, then scan the table for race-day targets.
The formula
Pace and speed are reciprocals: pace measures time per unit of distance (what runners use), speed measures distance per unit of time (what vehicles use). A 5:00/km pace equals 12 km/h, and equals about 8:03 per mile, since a mile is 1.609 km.
Worked example
Run 10K in 50:00 and your pace is exactly 5:00 per km — 8:03 per mile, 12.0 km/h. Hold it and you would finish a 5K in 25:00, a half marathon in 1:45:29 and a marathon in 3:30:59 — the classic sub-3:30 target that many club runners chase.
Frequently asked questions
What is a good 5K time?
It depends entirely on age, sex and experience. For orientation: many beginners finish their first 5K in 30–40 minutes (6:00–8:00/km); regular recreational runners often run 25–30 minutes; competitive club runners go under 20 minutes; world-class is under 13 minutes for men and 14:30 for women. Improving your own previous time is the meaningful benchmark.
How do I convert pace between minutes per mile and per km?
Multiply pace per km by 1.609 to get pace per mile, or divide pace per mile by 1.609 to get pace per km. A 9:00/mile runner is a 5:36/km runner. The table above does the conversion for your specific run automatically.
What pace do I need for a sub-4-hour marathon?
Four hours for 42.195 km works out to 5:41 per km or 9:08 per mile. For a sub-3:30, it is 4:59/km (about 8:01/mile); for sub-3:00, 4:16/km (6:52/mile). Enter those finish times above to generate the full split table.
Why is my race prediction slower than the table shows?
Because even-pace projections ignore fatigue curves: runners typically slow 3%–8% when doubling race distance, which models like the Riegel formula (which raises time to the power 1.06 over distance ratio) account for. Use the table as a ceiling — train to make your longer-distance pace approach it.