Gross, not net, calories
The main number includes the energy cost of the full activity. The unloaded comparison estimates the same route without the pack.
Free load-carriage tool
Estimate gross energy use for a loaded walk using your pack weight, pace, route grade and terrain-not a generic walking multiplier.
Estimated gross energy
Complete the route fields to estimate calories, time and load-attributable energy.
This is a population-level planning estimate, not a wearable replacement, medical recommendation or safe-load prescription.
The calculator uses the Pandolf load-carriage equation, developed to estimate metabolic power from body mass, external load, walking speed, grade and terrain. It then converts modeled watts over your route time into kilocalories.
W is body mass in kilograms, L is carried load in kilograms, T is the published terrain factor, V is speed in meters per second and G is positive grade in percent.
The terrain factors shown here follow the U.S. Army Medical Department reference: 1.0 for blacktop, 1.1 for dirt road, 1.2 for light brush, 1.5 for heavy brush and 2.1 for loose sand.
The main number includes the energy cost of the full activity. The unloaded comparison estimates the same route without the pack.
Added calories isolate the modeled difference created by the pack. It does not mean every extra calorie came only from load in real conditions.
Weather, stops, pack position, fatigue, gait and mixed terrain can materially change real energy use. Field studies find meaningful error among walking equations.
General educational information only. Do not use a calorie estimate to choose a medically safe load. Get qualified guidance before loaded exercise if you have an injury, balance concern, cardiovascular condition, pregnancy or another condition affected by exercise.