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Running Pace Calculator

Pace, split times and race predictor.

Your pace
/km
/mi
Predicted finish (Riegel)
5K
10K
Half
Marathon

How to Use

  1. Enter the distance (or tap a preset like 5K).
  2. Enter your time in hours, minutes and seconds.
  3. See pace per km and per mile, plus predicted race times.

Calculation Method

Pace = total time ÷ distance. Race predictions use Riegel's formula: T₂ = T₁ × (D₂ / D₁)^1.06, which models endurance fade over longer distances.

Source: Riegel endurance prediction model (1981)

Examples

10 km in 50:00

Pace 5:00 /km · predicted half ≈ 1:50:xx

5 km in 25:00

Pace 5:00 /km · 8:03 /mi

Frequently Asked Questions

Riegel works best when you are trained for the target distance; it tends to be optimistic for the marathon if your endurance base is limited.

Yes — divide your goal time by the distance to get the pace you need to hold for each km or mile.

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Health & Fitness Disclaimer

The health and fitness calculations provided are estimates only and should not replace professional medical advice. Individual health needs vary based on medical conditions, medications, personal goals and activity level. Consult with a healthcare provider, registered dietitian, or certified fitness professional before making significant changes to your diet or exercise routine. Not medical advice.

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Last updated: May 24, 2026

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