Running costs about one kilocalorie per kilogram per kilometre, almost regardless of speed. Hills change that a lot: a 5% climb raises the cost by nearly a quarter. Fitness has a smaller effect – fitter runners are a little more economical.
How to use the Running Calorie Calculator
- Age (years)
- Body weight
- Resting heart rate – beats in 20 s
- Distance
- Average grade (%)
- Where
Results update as you type, every field has its own unit menu, and everything is calculated in your browser.
How it works
Enter your age, weight and resting heart rate (beats in 20 seconds), the distance, the average grade and whether you ran on a treadmill.
Inputs explained
| Field | What to enter |
|---|---|
| Age (years) | A number |
| Body weight | Units: kg, lb |
| Resting heart rate – beats in 20 s | A number |
| Distance | Units: km, mi, m, yd |
| Average grade (%) | A number |
| Where | Choose one: Outdoors, Treadmill |
What each result means
- Estimated VO₂ max = 15.3×(208 – 0.7×[Age (years)])÷([Resting heart rate – beats in 20 s]×3)
- Net calories burned = [Distance]÷1000×[Body weight]×[Grade factor]×[Where]×[fit]
- Gross calories (including resting) = [Distance]÷1000×[Body weight]×[Grade factor]×[Where]×[fit]×1.12
Example values
How the main result changes when Age changes and everything else stays at the example values above:
| Age (years) | Net calories burned (kcal) |
|---|---|
| 15 | 756 |
| 22.5 | 760 |
| 30 | 764 |
| 37.5 | 768 |
| 45 | 772 |
| 60 | 781 |
Formula
Net kcal ≈ distance (km) × weight (kg) × (1 + 4.5·grade) for uphill (ACSM running equation)
Downhill: cost falls to about 80% at −10%, then rises again · Outdoors ≈ 3% more than treadmill (air resistance)
Worked example
Inputs — Age (years): 30; Body weight: 75 kg; Resting heart rate – beats in 20 s: 20; Distance: 10 km; Average grade (%): 0; Where: Outdoors.
Results — Grade factor = 1; Estimated VO₂ max = 47.7 ml/kg/min; Net calories burned = 764 kcal; Gross calories (including resting) = 856 kcal.
Key terms
- Running economy
- Oxygen cost of running at a given speed.
Frequently asked questions
Does running speed change calories per km?
Only slightly – distance and weight matter most.
What are net calories?
Calories above what you would have burned resting anyway.
Why does the treadmill burn less?
There is no air resistance; a 1% incline compensates.
Does downhill running burn fewer calories?
Yes, down to about −10%; steeper descents cost more again.