Medical Disclaimer: This calculator provides a general estimate based on established research and is for educational purposes only, not a substitute for medical advice. Individual results can vary based on health conditions, so consult a qualified healthcare professional or registered dietitian before making significant changes to your diet, exercise, or health routine. Read our full Medical Disclaimer.
How Rucking Calories Are Calculated
Rucking is walking with a weighted backpack, often called a ruck. The calories you burn depend on what you and your pack weigh, how fast you walk, how steep the route is, and what the ground is like. This calculator feeds those details into a load carriage equation built by US Army researchers.
What the Rucking Calorie Estimate Measures
The result estimates the total energy you use while rucking. It is a gross figure, so it includes the energy your body would burn at rest anyway. It is not a reading of your own breathing or heart rate. For a quick trail estimate by terrain band instead, the Calories Burned Hiking Calculator uses activity MET values.
The Formula
Watts per kg of body weight = 1.16 + [0.19 + T x (1.78 x S^0.58 + 0.27 x S^4 + H)] x (1 + 1.96 x P^1.36)
Hill term H = 34 x S x G x (1 - 1.05^(1 - 1.1^(100 x G + 32)))
Calories per hour = watts per kg x body weight (kg) x 0.8604
S is speed in meters per second. G is grade as a decimal (5% is 0.05, and downhill is negative). T is the terrain factor, and P is pack weight divided by body weight. The 1.16 is a resting rate of 1 kcal per kg per hour. This is the US Army Load Carriage Decision Aid (LCDA) backpacking equation from 2022¹, with a hill term from the same team's 2019 walking study².
How This Calculator Computes Your Result
Enter body weight and pack weight in pounds or kilograms, then speed (mph, km/h or pace) and time, or distance and time. Add the average grade (negative for downhill) and pick a terrain. Weigh the loaded ruck on a scale for the pack weight.
The calculator converts to kilograms and meters per second, applies the formula, and rounds calories to whole numbers. It shows total calories and calories per hour, per mile and per km. It also reruns the walk with no pack to show what the pack adds, and shows the older Pandolf equation's estimate for comparison³. It accepts speeds of 2.0 to 4.4 mph, grades of -25% to 25%, and packs up to 66% of body weight, the heaviest load in the 2022 study¹.
What Your Result Means
Your result is the energy that ruck used, not a target. Here is what a 180 lb (82 kg) adult burns per hour on flat pavement, using the formula above¹:
Pack | 3.0 mph | 3.5 mph | 4.0 mph |
No pack | 305 kcal | 371 kcal | 464 kcal |
20 lb | 327 kcal | 399 kcal | 502 kcal |
30 lb | 343 kcal | 420 kcal | 530 kcal |
45 lb | 371 kcal | 457 kcal | 578 kcal |
Speed matters more than most people expect. With 30 lb, going from 3.0 to 4.0 mph adds about 190 kcal per hour, while adding a 45 lb pack at 3.0 mph adds about 65. A review of soldier load carriage notes the same: speed may raise energy cost more than added load⁶.
How Much Your Pack Adds
Walking energy cost rises faster than pack weight, not in a straight line¹. For a 180 lb person walking 3.0 mph on flat ground, the model gives:
Pack | Share of body weight | Extra kcal per hour | Extra vs no pack |
20 lb | 11% | 22 | 7% |
60 lb | 33% | 98 | 32% |
90 lb | 50% | 170 | 56% |
So a light pack adds less than its share of your weight, and a very heavy pack adds more.
Hills, Downhill and Terrain
For the same 180 lb walker with 30 lb at 3.0 mph on pavement, the estimate is about 343 kcal per hour on the flat, 493 at a 5% grade and 691 at 10%. Downhill costs less, but not zero: about 259 at -5% and 232 at -10%, rising again to 268 at -20%. The hill term came from data on 95 people walking on grades from -40% to 45%².
Terrain multiplies the walking part of the cost. These factors come from 1972 field measurements, as reviewed by Army researchers in 2015⁴:
Terrain | Factor |
Paved road, track or treadmill | 1.0 |
Dirt road or gravel path | 1.1 |
Trail with light brush | 1.2 |
Heavy brush | 1.5 |
Swampy or boggy ground | 1.8 |
Loose sand | 2.1 |
On loose sand, the same walk rises from 343 to about 613 kcal per hour.
Why This Calculator Uses the LCDA Model
Many rucking calculators use the 1977 Pandolf equation³, which tends to under-estimate with modern loads. In 16 men carrying 22.7 or 38.4 kg at 2.5 to 6.5 km/h, it under-predicted in every condition, by 12% to 33%⁵. In the 2022 Army study, Pandolf read low by about 0.44 watts per kg on average, against 0.01 for the LCDA equation¹. On seven older data sets the figures were 0.46 and 0.08¹. So the LCDA result is the main number here, and Pandolf is shown for comparison.
Building Up Your Ruck Safely
In soldiers, carrying loads is linked to blisters, lower limb and lower back injuries, and stress fractures⁶. The same review says load and volume should increase gradually, at a safe rate⁶. For soldiers, it suggests load carriage sessions no more than once every 10 to 14 days⁶.
Calories Burned Rucking per Hour by Pack and Speed
Calories per hour for a 180 lb (82 kg) adult on flat pavement. Pick your pack and speed to find the value.
- Under 350
- 350–399
- 400–449
- 450–499
- 500 and above
| Pack | Speed | ||
|---|---|---|---|
| 3.0 mph | 3.5 mph | 4.0 mph | |
| No pack | 305 | 371 | 464 |
| 20 lb (9 kg) | 327 | 399 | 502 |
| 30 lb (14 kg) | 343 | 420 | 530 |
| 45 lb (20 kg) | 371 | 457 | 578 |
Use the arrow keys to move between cells.
Rucking Calories per Hour by Grade
The same 180 lb walker with a 30 lb pack at 3.0 mph on pavement. Uphill costs far more, and downhill costs less but not zero.
- 180 lb walker, 30 lb pack, 3.0 mph
Show data table
| Grade | 180 lb walker, 30 lb pack, 3.0 mph (kcal per hour) |
|---|---|
| −20% (downhill) | 268 |
| −10% (downhill) | 232 |
| −5% (downhill) | 259 |
| 0% (flat) | 343 |
| 5% (uphill) | 493 |
| 10% (uphill) | 691 |
A Note on Accuracy
This is a model estimate, not a measurement. The LCDA equation was built mostly from young, healthy military adults, and even there individual results varied by about 0.6 watts per kg, around 10% of the average¹. It uses a fixed resting rate and does not know your fitness, pack fit, heat, fatigue or how often you stop. The hill and terrain parts were joined to the load equation in 2022 but not tested together with heavy packs, so steep or rough routes give rougher estimates¹.
Frequently Asked Questions
How many calories does rucking burn per hour?
For a 180 lb (82 kg) adult carrying 30 lb on flat pavement, about 343 kcal per hour at 3.0 mph and 420 at 3.5 mph. Hills, soft ground, a heavier pack or a faster pace raise it¹.
Does rucking burn more calories than walking?
Yes. At 3.5 mph on flat ground, a 30 lb pack raises a 180 lb person's burn from about 371 to 420 kcal per hour, roughly 13% more¹.
How many calories does rucking burn per mile?
About 114 to 132 kcal per mile for a 180 lb person carrying 30 lb at 3.0 to 4.0 mph on flat pavement. A heavier body, a heavier pack or hills raise the cost per mile¹.
How accurate is a rucking calorie calculator?
It gives a reasonable estimate, not an exact count. The LCDA equation matched lab measurements closely on average, while the older Pandolf equation used by many calculators tends to read low¹ ⁵.
Sources
Modeling the Metabolic Costs of Heavy Military Backpacking, Looney et al., 2022
Estimating Energy Expenditure during Level, Uphill, and Downhill Walking, Looney et al., 2019
Predicting Energy Expenditure with Loads While Standing or Walking Very Slowly, Pandolf et al., 1977
Terrain Factors for Predicting Walking and Load Carriage Energy Costs, Richmond et al., 2015
The Pandolf Equation Under-Predicts the Metabolic Rate of Contemporary Military Load Carriage, Drain et al., 2017
Soldier Load Carriage, Injuries, Rehabilitation and Physical Conditioning, Orr et al., 2021