Tools
Rucking calorie calculator
How much energy a loaded walk really costs — from bodyweight, pack weight, pace, gradient and terrain.
Rucking calorie calculator
kg · km — change in the headerPandolf equation (1977) with the Santee downhill correction (2001). An estimate for a healthy adult, not a measurement — individual economy varies by 10–15%.
How this works
What the equation actually does
The Pandolf equation (Pandolf, Givoni & Goldman, 1977) estimates metabolic rate in watts from five inputs: bodyweight, carried load, walking speed, gradient and a terrain coefficient. It was developed for military load-carriage research and remains the reference model for the problem.
Its useful property is that the load term is non-linear — it scales with the square of the load-to-bodyweight ratio. Carrying 10% of your bodyweight costs far less than half of what carrying 20% costs, which a flat multiplier cannot express.
The downhill correction
Pandolf alone overestimates the cost of walking downhill, because it treats negative gradient symmetrically with positive. Descending is eccentric work and genuinely cheaper metabolically — though harder on your knees.
This calculator applies the Santee correction (2001) for negative grades, and floors the result at resting metabolic rate, because no walk costs less than lying still.
How to read the result
The panel shows what the same walk would cost with an empty pack alongside the loaded figure. That difference is what the load is buying you, and it is usually smaller than people expect — which is the honest argument for adding distance before adding weight.
Treat the number as an estimate. Individual walking economy varies by 10 to 15% between people of the same size, and no equation sees your gait.
What it does not include
Excess post-exercise oxygen consumption, the elevated burn after you stop, is not modelled. Neither is wind, altitude, temperature, nor the metabolic cost of carrying weight on your feet rather than your back — boots are roughly five times more expensive per kilogram than pack weight.
Common questions
How many calories does rucking burn?
An 80 kg person carrying 15 kg for 8 km in 90 minutes burns roughly 550 kcal. The figure moves substantially with pack weight, gradient and terrain — loose sand can more than double the cost of the same walk on tarmac.
Is this more accurate than a standard calorie calculator?
It is more appropriate for load carriage. Generic calculators apply a MET value for walking and sometimes a flat multiplier for a pack. The Pandolf equation models the load term non-linearly and includes gradient and terrain, which is why it is the standard in load-carriage research.
Does pack weight or distance matter more for calories?
Distance, by a wide margin. Doubling distance roughly doubles the energy cost; doubling pack weight from 10 to 20 kg on an 80 kg person adds nearer 15%. Weight is a strength stimulus more than a calorie one.
Why does the calculator ask about terrain?
Because surface changes energy cost more than most people expect. Walking in loose sand costs about 2.1 times what the same walk costs on pavement, and soft snow about 2.5 times.
Related: rucking vs running, load progression planner, and how heavy your ruck should be.