How Many Calories Does Hiking Burn? The Pandolf Equation
Ask how many calories a hike burns and you will often get a single number per hour, as if a stroll on a paved path and a steep climb with a pack cost the same. They do not, and the difference is large. The Hiking Calorie Burn Calculator uses a model built for exactly this question: the Pandolf load-carriage equation, developed by Kent Pandolf, Baruch Givoni and Ralph Goldman in 1977 from studies of people walking with loads. This guide explains what goes into it, runs it seven ways on the same distance, and is clear about where it falls short.
The equation in plain words
Pandolf estimates your metabolic rate, the energy your body is using per second, in watts:
M = 1.5W + 2.0(W + L)(L/W)² + η(W + L)(1.5V² + 0.35VG)
where W is your body mass in kilograms, L is the load you carry, V is walking speed in metres per second, G is the grade in percent, and η (eta) is a terrain factor. It has three parts:
- Standing cost, 1.5W. What it takes simply to stand upright. For a 70 kg person, 105 watts.
- Load cost, 2.0(W + L)(L/W)². The extra effort of supporting a pack. It grows with the square of the pack's share of your body weight, so it is small for light day packs and rises steeply for heavy ones.
- Movement cost, η(W + L)(1.5V² + 0.35VG). The effort of moving your body and pack along and up. It rises with speed, rises with grade, and is multiplied by the terrain factor.
The calculator turns watts into kilocalories over the time the walk takes (distance divided by speed). The terrain factors it offers run from 1.0 for a paved path or boardwalk, through 1.1 for a dirt road or firm trail and 1.2 for a rocky or rooty trail, to 1.5 and 1.8 for light and heavy brush, 1.6 for loose snow and 2.1 for soft sand.
Seven runs on the same 10 km
Take a 70 kg hiker with a 5 kg day pack walking 10 km at 4 km per hour, which takes two and a half hours. Change one thing at a time:
| Conditions | Metabolic rate | Calories |
|---|---|---|
| Paved path (1.0), level | 245 W | 526 kcal |
| Firm trail (1.1), level | 259 W | 556 kcal |
| Firm trail, 5% grade, no pack | 397 W | 855 kcal |
| Firm trail, 5% grade | 419 W | 901 kcal |
| Rocky trail (1.2), 5% grade | 447 W | 962 kcal |
| Firm trail, 10% grade | 579 W | 1,246 kcal |
| Firm trail, 10% downhill | 105 W (floor) | 226 kcal |
The same ten kilometres costs anywhere from about 230 to about 1,250 kcal. Three lessons stand out:
- Grade dominates. Going from level to a steady 5% climb adds about 345 kcal; going to 10% more than doubles the level-ground figure. Climbing is where hiking's energy goes.
- Terrain matters, but less than grade. Rocky ground instead of firm trail adds about 60 kcal on the 5% climb.
- A light day pack costs little. The 5 kg pack adds about 46 kcal on the 5% climb compared with no pack at all. The load term is small for light loads; see whether a heavier pack burns more calories for what happens as the load grows.
The descent problem
The last row needs explaining. Pandolf's movement term includes speed times grade, so on a downhill the grade is negative and the term shrinks. On steep descents the arithmetic can even go below the cost of standing still, which cannot be right: walking downhill takes effort to control your speed and absorb each step. The calculator therefore floors the rate at standing metabolism, 1.5 watts per kilogram of body weight, which is why the descent row shows exactly 105 watts.
That floor stops the answer going absurd, but it means the calculator under-counts steep descents. The original 1977 equation is known to underestimate downhill costs, and later researchers proposed correction terms for it. Treat any downhill figure from the calculator as a minimum.
Modelling a real out-and-back
Most hikes go up and then come down. Putting a single average grade over the whole distance would pretend you climb the entire way, so the honest approach is to run the climb and the descent as separate legs and add them.
Say the same hiker walks 5 km up at an average 10% grade, more slowly, at 3 km per hour, and 5 km back down at 4 km per hour:
- Up: 432 W for 1.67 hours, about 620 kcal.
- Down: the 105 W floor for 1.25 hours, about 113 kcal.
- Total: about 733 kcal, with the descent figure a known underestimate.
So a realistic estimate for this 10 km hill walk is somewhere above 733 kcal, and the true descent cost could add noticeably to it. Compare that with the 1,246 kcal you get by pretending the whole 10 km climbs at 10%: splitting the legs keeps the estimate honest.
What the estimate leaves out
Pandolf gives an estimate for an average person, and real burn varies. It does not know about:
- Individual efficiency. Fitness, technique and body build all change how much energy a given walk costs you.
- Uneven pace. Stopping and starting, scrambling, and stepping over obstacles cost more than steady walking at the average speed.
- Temperature. Keeping warm in the cold, or cooling in the heat, costs energy that the equation does not include. See cold-weather hiking.
- Altitude. Not modelled.
- Your stops. The calculator's time is distance divided by speed: moving time only.
It is a planning tool, not a medical or dietary measurement. If you are managing weight, diabetes or another health condition, use the figure as a rough guide and talk to a doctor or dietitian about what it means for you.
Using the number
The most useful thing to do with a calorie estimate on a hike is to make sure you carry enough food. Running low on energy makes you slower, colder and more prone to poor decisions late in the day, exactly when the descent and the light are working against you. Our guide to turning calories into a food bag works through that step.
It also helps with choosing routes. If you know a 10% climb roughly doubles the hourly cost of level walking, you can see why a short, steep hike can feel harder than a long, flat one. The Trail Difficulty Rating captures the same idea in a single number by combining distance and climb.
Getting good inputs
- Body mass and pack: weigh both. A bathroom scale with and without the loaded pack gives the pack weight.
- Speed: use your real moving speed, not your flat-pavement speed. The Hiking Time Calculator's estimate divided into the distance is a reasonable starting point.
- Grade: for each leg, the height gained divided by the distance, times 100. A 5 km leg climbing 500 m is 10%.
- Terrain: pick the factor that matches most of the route, and round up if you are unsure.
Treat the answer as a sensible estimate, carry more food than it suggests, and enjoy the knowledge that the hill really was as hard as it felt.