Pick what to solve for - pace, finish time or distance - and fill in the other two; the result updates as you type. The form starts pre-filled with a 5K in 25:00 so a real answer (5:00 min/km) is visible immediately. Overwrite the distance or pick a race preset from 5K to marathon, switch between kilometers and miles (entered values convert in place), and read the pace both ways, the speed in km/h and mph, and an even-pace split table for the standard checkpoints below the result.
Pace Calculator
The pace calculator solves the runner's triangle: enter any two of distance, time and pace and it gives you the third, entirely in your browser.
Ask it what pace finishes a 10K in 50 minutes, what a marathon takes at 6:00 min/km, or how far you covered in 40 minutes at your usual pace - the answer updates as you type.
Key features
- Pace always shows both ways - min/km and min/mile - together with the speed in km/h and mph.
- A race-preset list fills in the exact 5K, 10K, half-marathon (21.0975 km) and marathon (42.195 km) distances.
- Switching between kilometers and miles converts the distance and pace you already entered in place instead of resetting the form.
- An even-pace split table projects cumulative times at 1 km, 1 mile, 5K, 10K, 15K, half marathon, 30K and the full marathon, assuming a perfectly even pace - treat it as a planning estimate, not a coaching plan, since real splits vary with terrain, weather and fatigue.
When to use it
Use it to line up a treadmill setting, a race plan and a GPS watch reading side by side - the pace shown both ways means nothing needs converting by hand first.
Privacy
Nothing you type is stored or sent anywhere, and no account is needed.
Related calculators
- The percentage calculator handles generic percent questions rather than pacing.
- The fuel cost calculator does trip math in money rather than minutes.
- The TDEE calorie calculator estimates the day's energy burn that training sits inside.
Frequently Asked Questions
What does the pace calculator do?
It solves the runner's triangle: pick which of distance, time or pace to compute, enter the other two, and the result updates as you type - with the pace shown in both min/km and min/mile, the speed in km/h and mph, and an even-pace split table at the standard race checkpoints.
How do I convert a min/km pace to min/mile?
You do not have to - every result shows the pace both ways. A mile is 1.609344 km, so a 5:00 min/km pace reads 8:03 min/mile, and switching the unit select converts the numbers you already entered in place instead of clearing them.
What pace do I need to finish a marathon in 4 hours?
Pick the marathon preset (42.195 km), enter 4:00:00 and solve for pace: 5:41 min/km, which is 9:09 min/mile. The split table below the result then shows the even-pace passing times at 5K, 10K, half and 30K for that plan.
Are the split times exact race predictions?
No. The table projects a perfectly even pace, and real race splits vary with terrain, weather and fatigue. Use it as a planning estimate - a pacing target per checkpoint - not as a coaching plan or a guarantee.
Does anything I enter leave my browser?
No. The math runs locally in the page - nothing is uploaded, stored or sent, no account is needed, and the tool does not read a GPS watch or training app; every number is one you type in.