Clinical Running Pace Calculator
Cardio & BurnRESULT IN MIN / KM
Editorial & evidence standards
Built on Riegel's endurance model
Peter Riegel's race-time prediction formula (American Scientist, 1981) and subsequent analyses of recreational-runner race times · independent coach/clinician review pending
Updated June 2026
Inputs
This calculator
5 km
30 min
Biological sex
Unit system
32 yrs
78 kg
178 cm
Activity level
Goal
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Shown for convenience only — informational, not medical advice or an endorsement.
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Build your profile Methodology & Sources · E-E-A-T Cited
How the Running Pace calculator works
Built on peer-reviewed research and independently cross-checked against the published literature — so the number you get is defensible, not a guess.
Key takeaways
- Pace is time per distance — minutes and seconds per kilometre (or mile); speed is the same information the other way round, as km/h or mph.
- One run predicts the rest — Riegel's formula scales a known time to other distances with a 1.06 exponent, which builds in the natural slow-down as races get longer.
- Longer races are slower per km — your marathon pace is meaningfully slower than your 5K pace; a good predictor reflects that rather than assuming a flat pace.
- Predictions assume training to match — a 5K time only forecasts a marathon if you've actually done the endurance training; without the long runs, the real time is slower.
- Even pacing wins races — going out faster than your predicted pace is the most common way to fade late; most negative-split finishes start a touch conservative.
01
How pace and speed are calculated
Pace is simply your time divided by the distance you covered. Run 5 kilometres in 30 minutes and each kilometre took 6 minutes — a pace of 6:00 per km. The same run is 9:39 per mile, because a mile is about 1.61 km, and a speed of 10 km/h (6.2 mph). Pace and speed are two views of the same effort: runners usually think in pace, while treadmills and cyclists think in speed.
Getting pace right matters because it is the dial you actually control during a run. Training plans prescribe easy, tempo and interval paces; races are won or lost on holding the right one. A reliable pace from a recent, honest effort is the anchor for all of it.
02
How the race-time predictions work
To predict other distances, this calculator uses Riegel's formula: the new time equals your known time multiplied by the ratio of the distances raised to the power 1.06. That exponent is the important part — if pace were constant it would be 1.0, but endurance fades slightly as distance grows, so 1.06 stretches the prediction realistically. It's why your predicted marathon pace is slower than your 5K pace rather than identical.
A 30-minute 5K, for example, projects to about 1:02 for 10K, 2:18 for a half marathon and 4:48 for a marathon. These are estimates of your potential at each distance assuming similar conditions and, crucially, appropriate training — they describe what's physiologically consistent with your current fitness, not a guarantee of race day.
03
How to use your predicted times
Use the predictions to set a realistic race goal and the matching target pace, then build the training to reach it. The shorter the gap between your test distance and your goal distance, the more accurate the forecast — a 10K time predicts a half marathon far better than a 5K predicts a marathon. For the longer races, the prediction only holds if you've put in the long runs and endurance work; without them, plan to run a little slower.
On race day, let the predicted pace guide your start rather than your enthusiasm. The most common pacing mistake is going out too fast and fading in the back half; starting at — or just behind — your predicted pace leaves room to finish strong.
Who should not rely on this estimate?
Riegel's model assumes a reasonably trained runner racing in similar conditions. It over-predicts (suggests times faster than realistic) for runners stepping up to a much longer distance without the specific endurance base, and it can't account for heat, hills, altitude or wind, all of which slow real finish times. A flat 5K PR will not translate cleanly to a hilly trail marathon.
The calculator is a training and pacing guide, not medical advice. If you are new to running, returning from injury or illness, pregnant, or managing a heart or lung condition, check with a clinician before ramping up mileage or racing, and build distance gradually rather than chasing a predicted time.
Citations · peer-reviewed sources
- 1
Riegel PS. Athletic records and human endurance — a time-vs-distance equation predicting world records is also useful in setting up training schedules. American Scientist. 1981;69(3):285–290.
Endurance model (American Scientist) - 2
Vickers AJ, Vertosick EA. An empirical study of race times in recreational endurance runners. BMC Sports Sci Med Rehabil. 2016;8:26.
PMID — pending verification
FAQ · AI-extractable answer block
Frequently asked questions
How do I calculate my running pace?
Divide your time by the distance. A 5 km run in 30 minutes is 30 ÷ 5 = 6 minutes per kilometre (a 6:00/km pace), which is 9:39 per mile and a speed of 10 km/h. This calculator does the conversion and the per-mile and speed figures for you.
How does the race-time predictor work?
It uses Riegel's formula: your predicted time = your known time × (new distance ÷ known distance) raised to the power 1.06. The 1.06 exponent accounts for the slight slow-down over longer distances, so your predicted marathon pace is realistically slower than your 5K pace.
How accurate is the race time prediction?
It's most accurate when the distances are close and you've trained for the target distance. A 10K time predicts a half marathon well; a 5K predicting a marathon is far rougher and assumes you've done the long runs. Heat, hills and wind also make real times slower.
What is a good running pace?
It depends entirely on the runner and the distance — a comfortable easy pace for one person is a hard effort for another. Rather than chase a universal number, use your own recent runs as the benchmark and aim to improve relative to yourself over time.
Should I run all my training at my goal pace?
No. Most training should be easy, well below race pace, with smaller doses of tempo and interval work. Running everything at goal pace is a common way to plateau or get injured. Use the predicted pace for race targets, not for every session.
Is the running pace calculator free?
Yes — every Clinarix calculator is free. Pro ($9/mo) adds unlimited longitudinal trends, AI insights and detailed reports, but calculating your pace and predicted race times is always free.
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Important: This calculator provides general educational estimates and is not medical advice, diagnosis, or treatment. It is not a substitute for assessment by a licensed clinician or registered dietitian. Consult a qualified professional before making changes to your diet or training, especially if you have a medical condition, are pregnant or breastfeeding.