Suggested next steps
Continue this workflow
Move to a practical next or previous step without transferring your entered values.
About Running Pace Calculator: Min/Km, Min/Mile & Race Splits
Running Pace Calculator converts between race distance, finish time, running pace per kilometer or mile, and speeds in km/h and mph.
It uses Pete Riegel’s endurance scaling formula to predict equivalent finish times across standard race distances from 5K up to a full marathon.
How the calculation works
Pace conversion
Pace (seconds/distance) = Total elapsed seconds ÷ Distance in km or miles.
Riegel race prediction equation
T2 = T1 × (D2 / D1)^1.06, modeling fatigue accumulation over longer distances.
How to use this calculator
- 1Choose a standard distance preset (5K, 10K, Half Marathon, Marathon) or enter a custom distance.
- 2Enter your goal or actual race finish time (hours, minutes, seconds).
- 3Review pace per kilometer and mile, alongside running speed.
- 4Examine Pete Riegel equivalent race predictions for other distances.
Understanding the result
Even small 5-second per kilometer pace improvements compound into substantial finish-time gains across long distances like half or full marathons.
Riegel predictions assume equivalent aerobic conditioning for the longer distance.
Important limitations
- Weather conditions, course hills, humidity, and race-day nutrition can significantly impact actual pace compared to flat-course projections.
- Does not substitute for personalized cardiovascular endurance training.
Explore this topic
Frequently asked questions
What is a 5-minute per kilometer pace in miles?
A 5:00 /km pace equals approximately an 8:03 /mile pace.
What is the Riegel formula?
The Pete Riegel formula (T2 = T1 × [D2/D1]^1.06) is a widely validated athletic model that predicts race times across distances by accounting for aerobic fatigue.
Is my running data uploaded?
No. All calculations run strictly in your web browser.
Related tools
Selected from curated relationships first, then the same subtopic and category.