Running Pace Calculator

Work out your pace per km and per mile, and predict 10K, half marathon and marathon times.

km

Your result

Pace per km5:00
Pace per mile8:03
Predicted 10K52:07
Predicted half marathon1:55:00
Predicted marathon3:59:47

Updates as you type. Based on 2025/26 UK figures where relevant.

How this is worked out

Pace = time ÷ distance. Race predictions use Riegel's formula: T2 = T1 × (D2 ÷ D1)^1.06.

Tips

  • The NHS uses BMI as a screening tool, but waist measurement also matters.
  • Estimates like BMR and body fat can vary by 5–10% from lab measurements.
  • Track trends over weeks rather than day-to-day changes.

Frequently asked questions

How does the running Pace Calculator work?

Pace = time ÷ distance. Race predictions use Riegel's formula: T2 = T1 × (D2 ÷ D1)^1.06.

Is this medical advice?

No. These tools give general estimates. For medical advice, speak to your GP, pharmacist or NHS 111.

Can I use these for children?

No. Children's BMI and health measures use age- and sex-specific charts. Use the NHS healthy weight calculator for children.

Why use stone and pounds?

Many people in the UK still think in stone and pounds, so we accept those units and show metric too.

This calculator gives an estimate for general information. It isn't financial, tax, legal or medical advice. Check official figures on GOV.UK or NHS.uk, or speak to a qualified adviser.