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    Rucking Calorie Calculator

    Estimate how many calories you use walking with a weighted backpack on level ground — and how much the pack adds compared with the same walk without it.

    Level ground only. Results update as you type.

    70.0 kg (154.3 lb)

    Up to 66% of body weight. 0 = no pack.

    1.7–7.0 km/h (1.1–4.3 mph), flat ground

    Estimated active calories

    230 kcal

    Energy for walking with the pack, resting energy excluded

    Estimated total calories

    300 kcal

    Includes 70 kcal resting energy. Do not add to active kcal.

    Distance

    5.00 km (3.11 mi)

    60 min on level ground

    Same walk without a pack

    202 kcal active

    272 kcal total

    Pack changes active calories by

    +14%

    28 kcal more active energy. Total rises by 10%.

    Load used

    14% of body weight

    10.0 kg (22.0 lb) pack

    Compare two pack weights

    Pack A · 10.0 kg (22.0 lb)

    230 active · 300 total kcal

    Pack B · 20.0 kg (44.1 lb)

    274 active · 344 total kcal

    B vs A

    +44 kcal (+19% active)

    Estimates only. Individual energy use can differ substantially from these values.

    How the estimate works

    The calculator uses the backpacking equation published by Looney and colleagues (equation 2), built from treadmill measurements of people walking with loaded military rucksacks:

    Energy (W/kg) = resting + (0.19 + 1.78 × S0.58 + 0.27 × S4) × (1 + 1.96 × L1.36)

    S is walking speed in metres per second and L is pack weight divided by body weight. The pack multiplies the cost of walking instead of being added to body weight, so light packs change little and heavy packs add disproportionately more.

    Active calories are the walking part of the equation. Total calories also include resting energy for the same time, estimated at 1 kcal per kg per hour because your measured resting rate is not known. They are two views of the same walk — never add them together. Watts are converted with 1 kcal = 4.184 kJ.

    Worked example

    70 kg (154 lb) person, 5 km/h (3.1 mph) for 60 minutes, so S = 1.389 m/s:

    • No pack: 0.19 + 1.78 × 1.3890.58 + 0.27 × 1.3894 = 3.35 W/kg → 234 W → about 202 active kcal (272 total).
    • 10 kg (22 lb) pack, L = 0.143: load factor 1.139 → 3.81 W/kg → about 230 active kcal (300 total), +14% active.
    • 20 kg (44 lb) pack, L = 0.286: load factor 1.357 → 4.54 W/kg → about 274 active kcal (344 total), +36% active.

    The extra percentage depends on body weight, pack weight and speed; walking time changes the calories but not the percentage.

    Limits of this estimate

    • Level ground only. Hills, stairs, sand, snow and trails are not included.
    • Speeds 1.7–7.0 km/h (1.1–4.3 mph) and packs up to 66% of body weight — the ranges the study measured.
    • The study used backpacks with a mainly young, military population. It was not specifically validated for weighted vests.
    • The equation predicted group averages well, but individual results can differ substantially. Treat every number as an estimate, not a measurement.
    • Loads above 30% of body weight are flagged. Showing a heavy load here is not a recommendation to carry it.

    Source: Looney DP, Lavoie EM, Vangala SV, et al. Modeling the Metabolic Costs of Heavy Military Backpacking. Med Sci Sports Exerc. 2022;54(4):646–654.