How rucking calories are calculated
This calculator uses the Pandolf equation (Pandolf, Givoni & Goldman, 1977), developed by the US Army to predict the energy cost of marching with a load. It accounts for your body weight, pack weight, speed, incline and terrain.
M (watts) = 1.5W + 2.0(W + L)(L/W)² + η(W + L)(1.5V² + 0.35VG)
kcal per minute = watts × 0.01433
W is body weight and L pack weight in kg, V speed in m/s, G incline in percent and η the terrain factor. Downhill walking needs a different correction, so the calculator covers flat and uphill only.
Terrain factors
| Terrain | Factor (η) |
|---|---|
| Paved road or treadmill | 1 |
| Dirt road | 1.1 |
| Light brush | 1.2 |
| Heavy brush | 1.5 |
| Loose sand | 2.1 |
| Soft snow (15 cm) | 2.5 |
Calories per mile rucking
At a steady 3 mph on flat ground, an 80 kg (176 lb) person carrying 20 kg (44 lb) burns about 115 kcal per mile. A 5% incline raises that to about 183 and loose sand to about 200, while 5 kg more in the pack only takes it to about 121.
Choosing a ruck weight
- Start around 10% of body weight and build toward 20–25% over weeks.
- Increase distance or time before adding weight.
- Keep the load high and tight on your back to protect posture.
Studies of modern military loads found the Pandolf equation can under-predict energy use by 12–33%, so treat results as a conservative estimate.
Frequently asked questions
How many calories does rucking burn?
An 80 kg person carrying 20 kg at 3 mph on flat ground burns roughly 350 kcal an hour, versus about 290 kcal walking at the same pace without it. Hills, sand and heavier packs raise it sharply.
How heavy should my ruck be?
A common starting point is about 10% of body weight, building gradually toward 20–25%. Increase distance before weight, and keep good posture.
How accurate is the Pandolf equation?
It is the standard military load-carriage model, validated for loads up to about 40 kg, speeds up to 6 km/h and grades up to 10%. Later studies found it can under-predict energy use with modern military loads by 12–33%, so treat results as a conservative estimate.
General fitness information, not medical advice. Results are estimates; check with a doctor or qualified coach before major changes to diet or training. Last reviewed 2026-09-27.