Rucking calories calculator

For general information only — not medical advice. Heavy loads strain the back, hips, knees and feet. Talk with your doctor before you start, especially if you have heart, back or joint problems or have been inactive, and build load and distance up slowly. How we check our calculators.

What the number is

Rucking is walking with a weighted pack. The calories you burn rise with the load, the speed, the slope and how soft the ground is, and they rise faster than the pack weight alone. Both equations used here predict your total metabolic rate in watts, which the page converts to kilocalories (1 kcal is 4,184 joules, so 1 watt for an hour is about 0.86 kcal). Because the total includes standing energy, compare it with what you would burn doing nothing for the same hour.

The two equations

Pandolf (1977): M = 1.5W + 2.0(W + L)(L/W)² + η(W + L)(1.5V² + 0.35VG), where W is your weight, L the load, V speed in m/s, G grade in percent and η the ground factor. LCDA (Looney 2022, with the grade term from Looney 2019): M/W = M_rest + [0.19 + η(1.78·S^0.58 + 0.27·S⁴ + M_grade)] × (1 + 1.96·L_bp^1.36), where L_bp is the pack weight divided by body weight and M_grade = 34·S·G·(1 − 1.05^(1 − 1.1^(100G + 32))) with G as a fraction. The ground factors on this page run from 1.0 for blacktop to 2.1 for loose sand.

How many calories does rucking burn?

It depends on your weight, the pack, your speed, the slope and the ground. For a 175 lb person carrying 35 lb at 3 mph on level pavement the LCDA equation gives about 350 kcal per hour, and the Pandolf equation about 330. Without the pack the same walk is about 302 kcal per hour by LCDA, so the pack adds roughly 48 kcal an hour. These totals include the energy you would spend just standing, not only the extra from the walk.

What is the Pandolf equation?

It is a 1977 equation from Pandolf, Givoni and Goldman that predicts the metabolic rate in watts of a person standing or walking with a load: M = 1.5W + 2.0(W + L)(L/W)² + η(W + L)(1.5V² + 0.35VG). Here W is body mass and L the load (both kg), V is speed in meters per second, G is the grade in percent and η is a terrain factor. For a 70 kg person walking 1.34 m/s (3 mph) on a level blacktop road it gives 294 W without a load.

What is the LCDA equation, and why show it as well?

LCDA stands for the US Army Load Carriage Decision Aid, a planning tool. Looney and colleagues at the US Army Research Institute of Environmental Medicine (USARIEM) measured 30 mostly male, military-age adults carrying rucksacks of up to 66% of body mass at 0.45 to 1.97 m/s, and fitted a new equation: resting rate + (0.19 + 1.78·S^0.58 + 0.27·S⁴) × (1 + 1.96·(load/body mass)^1.36) in W/kg, where S is speed. On their data the Pandolf equation read 0.44 W/kg too low on average, while LCDA was off by about 0.01. A separate 2017 study of 16 men also found that Pandolf under-predicts modern military loads, by 12% to 33%.

Which result should I trust?

Use LCDA for loads in a rucksack at walking speed, the case it was fitted to, and treat Pandolf as a second opinion. In the example the two differ by about 20 kcal over the hour; they can differ more with heavy loads. Neither is a measurement of you: in the LCDA study the scatter of estimates around the measured values (one standard deviation) was about 0.63 W/kg, which for an 80 kg person is about 50 W, or 43 kcal per hour, so individuals differ from the average prediction.

Worked example: what changes the number

Start from the 175 lb person with 35 lb at 3 mph on pavement: 350 kcal in an hour (LCDA). A 5% uphill grade raises it to 502. Loose sand (terrain factor 2.1 against 1.0 on blacktop) raises it to 623. Carrying 60 lb instead of 35 lb, which is 34% of body weight, gives 401. Terrain and slope matter at least as much as pack weight.

How heavy should my ruck be?

There is no single safe percentage, and the Army manual does not use a ‘30% rule’. Chapter 5 of Army field manual FM 21-18 (Foot Marches, 1990) says the fighting load of a conditioned soldier should not exceed 48 pounds and the approach march load should not exceed 72 pounds, including all clothing and equipment. It also notes that soldiers who meet the Army fitness test standards can carry loads of 45% of body weight (average 72 pounds) at 4 km/h for eight-hour approach marches, and that training should start with light loads and short distances. It adds that distance covered in six hours falls by about 2 km for every 10 pounds carried over 40 pounds. For most civilians, start lighter and build up.

Is rucking a safe workout?

It can be, but a heavy load on your shoulders and back raises the risk of back, foot and knee trouble if you add weight or distance too fast. Add load and distance a little at a time, wear shoes that fit, and stop if you have chest pain, dizziness, severe shortness of breath or sharp pain in a joint. If you have a heart condition, back or joint problems, or have been inactive, see your doctor first.

Limits of these equations

Both equations were built on laboratory treadmill walking by young, healthy, mostly male volunteers, and the LCDA backpack equation assumes a well-fitted military rucksack. They do not include wind, heat, boots or wet ground beyond the terrain factor, carrying weight in the hands, hiking poles, or going downhill (the calculator takes uphill grades only). The terrain factors multiply the speed and grade terms, and they are published values for soil conditions, not for your trail. The resting rate that LCDA needs is not given as a single number in the paper; this page uses 1.25 W/kg, the standing value of 1.44 W/kg from the 2019 meta-regression minus the 0.19 constant, which is our own derivation.

Sources and related calculators

Sources: K. B. Pandolf, B. Givoni and R. F. Goldman, “Predicting energy expenditure with loads while standing or walking very slowly,” Journal of Applied Physiology 43(4):577–581 (1977), equation as printed in secondary sources, the paper itself was not read; D. P. Looney and others, “Modeling the metabolic costs of heavy military backpacking,” Medicine & Science in Sports & Exercise 54(4):646–653 (2022); D. P. Looney and others, MSSE 51(2):346–351 and 51(9):1954–1961 (2019), abstracts only; J. R. Drain and others, “The Pandolf equation under-predicts the metabolic rate of contemporary military load carriage,” Journal of Science and Medicine in Sport (2017); US Army, FM 21-18 Foot Marches (1990), chapter 5, now replaced by ATP 3-21.18 (not opened). Related: calories burned calculator, steps to miles, sweat rate calculator, target heart rate calculator and calorie calculator.