Zone 2 heart rate calculator
Compare Zone 2 methods and see all five estimated heart rate training zones.
Running pace calculator
Find your pace, plan a finish time or see how far you can run. Every split, in kilometers or miles.
Your run
Example valuesChoose what to calculate, then enter the other two values.
No account needed. Calculations happen in your browser; your entries are not saved or sent to Century.
Example · Your running pace
5:00/km
At a constant 5:00 per km, 5.000 km takes 25:00.
- Finish time
- 25:00
- Average speed
- 12.00 km/h
| Distance | Cumulative time |
|---|---|
| 1.000 km | 5:00 |
| 2.000 km | 10:00 |
| 3.000 km | 15:00 |
| 4.000 km | 20:00 |
| 5.000 km | 25:00 |
How it’s calculated
Pace = elapsed time ÷ distance. Finish time = pace × distance. Distance = elapsed time ÷ pace. All calculations use seconds internally and the exact conversion of 1 mile = 1.609344 kilometers. Splits assume a constant pace, including any stops in your entered time. Values are rounded only for display; this is a pacing calculation, not a prediction of race performance.
Reference: NIST: mile-to-kilometer conversion
For general wellness information. This tool does not diagnose health conditions or replace medical advice.
Related tools
Plan your run with pace, time and distance
Use two values to find the third
Choose Pace to calculate an average from your distance and time. Choose Finish time to see how long a distance takes at a given pace. Choose Distance to see how far that pace takes you in the time available. Results update as you type, with no calculate button or signup.
Enter hours, minutes and seconds separately. Pace uses minutes and seconds per kilometer or mile: 5 minutes and 30 seconds means 5:30, not 5.30 decimal minutes. A blank or invalid required field pauses the result until you complete it.
Set a 5K, 10K, half-marathon or marathon target
Select a race preset to use its distance, then enter your target time or pace. The half-marathon preset uses 21.0975 kilometers and the marathon uses 42.195 kilometers. Miles are converted from those distances rather than using rounded 13.1 or 26.2 mile values.
The split table shows cumulative time at a constant pace, with the final partial kilometer or mile included. For longer distances, checkpoints are spaced farther apart to keep the table readable. Use these as reference points rather than a requirement to run every section identically.
Compare pace without losing the context of your run
Switching kilometers and miles changes how the same distance and pace are displayed. The underlying values stay consistent, so a 5 km run does not become a 5 mile run. Results are calculated before rounding to the nearest second for display.
A finish time calculated from pace assumes that pace is maintained throughout. It does not estimate whether you can sustain it. Consider the route and the purpose of the session when planning, and use Century to view running activity alongside your training load and recovery trends.
Frequently asked questions
How do I calculate my running pace?
Divide your total running time by your distance. A 5 km run in 25 minutes has an average pace of 5:00 per kilometer. Enter time and distance in this calculator to see pace, speed and even splits.
What pace do I need for a 25-minute 5K?
A 25-minute 5K requires an average pace of 5:00 per kilometer, or approximately 8:03 per mile. At an even pace, each kilometer takes five minutes and the first mile takes about eight minutes and three seconds.
How do I convert minutes per kilometer to minutes per mile?
Multiply seconds per kilometer by 1.609344 to get seconds per mile. For example, 5:00 per kilometer is 300 seconds × 1.609344 = 482.8032 seconds per mile, displayed as 8:03. Switching units in this calculator preserves the same physical distance and pace.
How do I calculate a marathon finish time from pace?
Multiply your pace per kilometer by 42.195, or your pace per mile by the marathon distance of approximately 26.2188 miles. At 5:00 per kilometer, an even-paced marathon takes 3:30:59 when rounded to the nearest second. This is arithmetic at a constant pace, not a performance forecast.
What is the difference between running pace and speed?
Pace is time per distance, such as minutes per kilometer. Speed is distance per time, such as kilometers per hour. A pace of 5:00 per kilometer is a speed of 12 km/h. A smaller pace number means a faster run.
Does the pace calculator include stops and hills?
The calculator uses the time you enter. Elapsed time includes stops; moving time excludes them. The split table assumes the same pace throughout and does not adjust for hills, weather, fatigue or aid stations. Choose the time measure that matches your goal.