Running Pace Calculator
Know two of distance, time, and pace? Enter them below to get the third instantly — plus your pace in min/km and min/mi, speed in km/h and mph, and a full split table for your race distance.
Solve for
Enter hours:minutes:seconds, minutes:seconds, or just minutes.
Enter minutes:seconds, e.g. 5:30 for 5 minutes 30 seconds.
Some values were far outside a realistic range and were capped for this calculation.
Splits
| # | Cumulative distance | Split time | Cumulative time |
|---|
Every calculation runs in your browser — nothing is sent to a server.
This tool gives training and planning estimates only — actual race performance depends on many factors, and this isn't professional coaching advice.
Enter any two of distance, time, and pace, then calculate the third.
Distance, time, and pace
Running performance is fully described by three linked numbers: how far you went, how long it took, and your pace. Fix any two and the third is determined. Pace is the time to cover one unit of distance — minutes per kilometre or minutes per mile — while speed is the same relationship flipped around: distance covered per unit of time. This calculator lets you enter the two values you know and solves for the third, then shows the result as both pace and speed.
How to use it
- Choose what to solve for — time, pace, or distance.
- Pick your unit, kilometres or miles, so the inputs and split table match the way you train.
- Enter the two values you know. Times accept hours:minutes:seconds, minutes:seconds, or plain minutes; paces accept minutes:seconds. The race presets fill in standard distances for you.
The formulas
Pace is time divided by distance; speed is distance divided by time. To convert between units, one mile is 1.609344 kilometres, so a min/km pace multiplied by 1.609344 gives min/mi, and a speed in km/h divided by 1.609344 gives mph.
Example 1 — solving for pace and speed. Run 10 km in 50:00. Pace is 50 ÷ 10 = 5:00 per km. Speed is 10 km ÷ (50/60 h) = 12.0 km/h. Converting, the pace is 5:00 × 1.609344 ≈ 8:03 per mile, and the speed is 12.0 ÷ 1.609344 ≈ 7.46 mph.
Example 2 — solving for time. To run a marathon (42.195 km) at 5:30 per km, multiply: 42.195 × 5.5 minutes = 232.07 minutes, which is 3 hours 52 minutes 4 seconds. That one line is the core of every goal-pace plan.
Example 3 — solving for distance. If you ran for 45:00 at a 6:00 per km pace, distance is 45 ÷ 6 = 7.5 km. Halving the pace number is not the same as doubling the distance, so it pays to let the tool do the arithmetic.
Pace, speed, and finish-time reference
| Pace (min/km) | Pace (min/mi) | Speed (km/h) | 10K time | Marathon time |
|---|---|---|---|---|
| 4:00 | 6:26 | 15.0 | 40:00 | 2:48:47 |
| 4:30 | 7:15 | 13.3 | 45:00 | 3:09:53 |
| 5:00 | 8:03 | 12.0 | 50:00 | 3:30:59 |
| 5:30 | 8:51 | 10.9 | 55:00 | 3:52:04 |
| 6:00 | 9:39 | 10.0 | 1:00:00 | 4:13:10 |
Reading your splits
The split table breaks your target into per-kilometre or per-mile segments so you can check your watch against a plan mid-race. Running each split at nearly the same time is an "even" pace; deliberately running the second half slightly faster than the first is a "negative split," which many runners find produces their best finishing times because it holds energy back for when it is hardest to keep going.
Common mistakes and limits
- Going out too fast. The most common way to miss a goal time is to bank time early and fade; the split table is there precisely to resist that urge.
- Trusting GPS to the second. Watches drift on tree-lined or twisty courses, often reading long, which makes your live pace look faster than it really is.
- Treadmill versus road. A treadmill's set belt speed and the lack of wind resistance make the same pace feel different from running outdoors.
These are planning and training estimates, not a performance guarantee. Real race times depend on terrain, weather, altitude, and how you feel on the day, and nothing here is professional coaching advice.
Sources & further reading
- American College of Sports Medicine — exercise intensity and endurance training guidance
- American Heart Association — physical activity recommendations for runners and walkers
- CDC — physical activity basics, including aerobic activity duration and intensity
- NIST — official unit conversions used for miles, kilometers, and speed
Frequently asked questions
How do I calculate my running pace from a race time?
Pace is your time divided by distance. Formula: pace per km = total time ÷ distance in km (or per mile = total time ÷ distance in miles). For example, if you run a 5K (5 km) in 25:00, your pace is 25:00 ÷ 5 = 5:00 per km — pick “Find Pace”, enter 5 km and 25:00, and this calculator does the division for you, showing the result in both min/km and min/mi.
How do I convert min/km to min/mile pace?
Multiply your pace in minutes per kilometer by 1.60934 (the number of kilometers in a mile) to get minutes per mile — a 5:00/km pace becomes about 5:00 × 1.60934 ≈ 8:03/mi. Going the other way, divide a min/mile pace by 1.60934 to get min/km. This calculator converts automatically: enter your pace in either unit and the result panel always shows both min/km and min/mi side by side.
Can this calculator predict my race finish time?
Yes — switch to “Find Time”, enter your goal race distance (use the 5K, 10K, half marathon, or marathon presets, or type a custom distance), and enter the pace you know you can hold from a recent race or training run. The calculator multiplies your pace by the distance to give a projected finish time, plus a full split table showing your cumulative time at every kilometer or mile along the way.
What time formats does the time field accept?
You can type hours:minutes:seconds (1:32:15), just minutes:seconds (45:00), or a plain number of minutes (45). The pace field works the same way for minutes:seconds — 5:30 means 5 minutes 30 seconds. The parser is tolerant of missing leading zeros and decimal seconds, so “1:5:9” and “1:05:09.5” both work.
Is my pace and distance data sent to a server?
No. Every calculation — distance, time, pace, speed, and the split table — runs entirely in your browser. Nothing is uploaded, there's no sign-up, and your last entries are only saved in your browser's local storage so the form remembers them next time. This isn't training advice from a coach; it's arithmetic based on the numbers you enter.