A 180 lb person rucking 30 lb at a 17 minute per mile pace on level pavement burns roughly 480 calories an hour. That is about 28% more than walking the same route with nothing on their back. Change the load, the pace, the grade or the surface and the figure moves a long way, so use the calculator below rather than the average.
Estimated burn
406 kcal ±10%
- 478 kcal per hour
- 135 kcal per mile
- +91 vs. walking it unloaded
All inputs within validated ranges.
Engine v1.1.0 · How this is calculated · What changed
Open Show the math under any result and the calculator prints its full working — every term, your own numbers substituted in, and a link to the paper each step comes from. If a figure looks wrong, you can find out why without taking anyone’s word for it.
What actually moves the number
Load, and not in a straight line
The penalty for carrying weight grows with the square of the load-to-body-weight ratio. Adding ten pounds to a 20 lb ruck costs you noticeably less than adding ten pounds to a 50 lb ruck. This is why heavy rucking gets hard faster than people expect, and why a fixed “calories per pound” rule of thumb cannot work.
Pace, also squared
Energy cost rises with the square of speed. Going from 3.0 to 3.5 mph costs more than the 17% the pace change suggests. Past about 4.4 mph most people break into a march-run, the walking equation stops describing what you are doing, and the calculator tells you so.
Surface, which is the one people underestimate
Loose sand costs 2.1 times what blacktop does at the same load and pace. Not 20% more — more than double. A 45 lb ruck at 3 mph that burns about 440 kcal/hr on pavement burns about 765 on soft sand.
Worth saying plainly: this site had that number wrong. It used 1.20 for sand, which under-reported beach rucks by roughly 35%. The full coefficient table now uses the measured values, and the correction is in the changelog.
Grade, in both directions
Uphill is obvious. Downhill is stranger: cost falls as the descent steepens, bottoms out near minus 10%, then climbs again as your legs shift from propelling to braking. Most rucking calculators handle descents badly or not at all — the underlying equation returns negative watts downhill without a correction applied. This page explains what goes wrong and how it is fixed.
View the numbers behind this chart
| Load carried | 2.5 mph | 3 mph | 3.5 mph | 4 mph |
|---|---|---|---|---|
| 0 lb | 237 | 295 | 363 | 442 |
| 10 lb | 254 | 319 | 396 | 485 |
| 20 lb | 273 | 345 | 431 | 532 |
| 30 lb | 295 | 376 | 472 | 585 |
| 40 lb | 321 | 410 | 519 | 648 |
| 50 lb | 350 | 451 | 575 | 723 |
| 60 lb | 372 | 481 | 616 | 778 |
How this calculator works
It runs the Pandolf equation, developed at the US Army Research Institute of Environmental Medicine in 1977 and still the standard model for load carriage, with three published corrections layered on top:
- A downhill correction, because the base equation is unusable on descents.
- A load-ratio correction, because the base equation is documented to under-predict modern loads by 21 to 33% at 4 mph.
- Measured terrain coefficients rather than estimates.
The unloaded comparison uses a separate walking equation, kept entirely separate from the ruck estimate so both stay auditable. Full detail, including the model’s known weaknesses, is on the methodology page.
Things this tool does that most don’t
- It shows its working. Every result expands into a full calculation trace with sources.
- It gives an error band, not a false-precision number. Roughly ±10% inside validated ranges, wider outside them.
- It tells you when you have left charted territory. Load over 70 kg, pace over 4.4 mph, descent past minus 12% — each gets flagged on screen with the range it exceeded.
- It handles descents. Many calculators either ignore negative grades or return figures below basal metabolism.
- It separates gross from net. Gross includes your resting metabolism, which is what a watch reports. Net strips it out. Both are shown, both labelled.
- It publishes what it gets wrong. The methodology page carries a standing list of the engine’s weaknesses, including one where it currently overshoots.
Quick reference
| Body weight | 10 lb load | 20 lb load | 30 lb load | 40 lb load | 50 lb load |
|---|---|---|---|---|---|
| 140 lb | 319 | 358 | 404 | 460 | 500 |
| 160 lb | 360 | 397 | 440 | 492 | 542 |
| 180 lb | 401 | 437 | 478 | 526 | 583 |
| 200 lb | 441 | 477 | 517 | 562 | 615 |
| 220 lb | 482 | 517 | 556 | 600 | 649 |
| 250 lb | 543 | 578 | 615 | 657 | 703 |
This table is generated by the same engine that powers the calculator, so the two can never disagree. More combinations, including pace and terrain variants.
Common questions
How many calories does rucking burn compared with walking?
At a typical recreational load — 20 to 30 lb at 3 to 3.5 mph — expect around 10 to 30% more than unloaded walking. A heavy pack on rough ground gets you to 50 or 60%, and only a heavy load at speed on a grade reaches roughly double. GORUCK’s own material describes rucking as burning two to three times walking; that upper figure needs a heavy pack, a brisk pace and a hill together, not a light ruck on a flat road.
Why does my watch give a different number?
Most wearables have no idea you are carrying anything. They estimate from pace, heart rate and your body weight, so a ruck looks to them like a brisk walk. Heart rate picks up some of the load cost indirectly, which is why the gap is usually smaller than you would expect, but it still typically under-reports. The calculator’s gross figure is the one to compare against your watch, since that is what watches report.
How accurate is this?
About ±10% with everything inside validated ranges, and the calculator widens that band and says why when you go outside them. Individual variation in gait economy, pack fit, training history and conditions is real and no equation captures it. Treat the figure as a solid planning number, not a measurement.
How much weight should I actually carry?
Beginners generally start around 10% of body weight and build slowly. A third of body weight is a widely used ceiling for non-military rucking. The ruck weight calculator works it out for your body weight, experience and goal.
Does rucking burn more than running?
Per hour, running usually wins. Per mile, a heavy ruck can close the gap or beat it, and it does so at much lower joint impact, which is a large part of why rucking appeals to people who cannot tolerate running volume.
Other tools
- Rucking pace calculator — pace, splits and finish time under load
- Ruck weight calculator — how much to carry
- Rucking calorie chart — reference tables by weight, pace and terrain
- Terrain coefficients — the full measured table