Running energy expenditure calculator

Calorie expenditure calculator for running

Scientific estimate based on your pace and the terrain

Understanding how many calories you burn during arunning session is useful for adjusting your diet, following an exercise program, or simply satisfying your curiosity as a runner. 

But between the figures displayed on your smartwatch, apps such as Garmin or Suunto, generic "kcal per hour" tables, and differences in intensity from one person to another, it's easy to get confused.

This calculator has been designed to provide the most accurate estimate possible of your energy expenditure when running, based on tools used in exercise physiology: METs (Metabolic Equivalent of Task) and ACSM ⁷ reference equations.

The goal is not to give you a figure down to the last calorie, but rather a solid estimate, accompanied by clear explanations so that you understand what lies behind the result.

Reminder: what is a calorie burned while running?

Total calorie expenditure over a day can be broken down into three main parts, which are already used in other Protéalpes calculators.

• Basal metabolic rate (BMR ): the minimum amount of energy required to keep the body functioning at rest (breathing, vital functions, temperature, etc.).
• Thermic effect of food (TEF): energy used to digest, absorb, and metabolize food (approximately 5–10% of daily energy expenditure).
• Physical activity: anything done beyond resting, from leisurely walking to marathons, including swimming, cycling, or running.

The running calorie calculator focuses on this third component: the energy expended during a run, based on weight, running speed, duration, elevation gain, and conditions (terrain, temperature, wind).

The scientific basis: METs (Metabolic Equivalent of Task)

METs are used to estimate energy expenditure during running:

• 1 MET = resting expenditure = approximately 1 kcal per kilogram of body weight per hour (1 kcal/kg/h).
• An activity with a MET value of 10 therefore means: 10 times more energy than at rest.

The Compendium of Physical^Activities and its 2024 update ^assign a MET value to each activity, particularly for running at different speeds.

Specifically, for the race:

• approximately 6 MET at 6.4 km/h,
• 8.3 MET at 5.0 mph,
• 9.8 MET at 9.7 km/h,
• 11 MET at 11.3 km/h,
• 12–14.5 MET for speeds above 13–16 km/h.

The calculator therefore begins by associating running speed with a basic MET, aligning itself with these references.

The central formula

Once the MET is known, gross calorie expenditure is calculated as follows:

Calories burned while running = MET × weight (kg) × duration (hours)

Simple example:

• 10 km/h for 1 hour, MET ≈ 10,
• Weight 70 kg → 10 × 70 × 1 = 700 kcal burned during this hour of running.

This is the same logic used in many metabolic equivalent tables, scientific studies, and several physical activity tracking applications.

From running speed to MET: how to proceed?

Speed (km/h) and pace (min/km)

In the calculator, the average speed in km/h is indicated (or varied directly in the interface). It is automatically converted into pace (minutes per kilometer) so that it makes sense to runners:

This running speed is then used to determine a baseline MET:

• < 6,4 km/h → ~6 MET (footing très lent, proche de la marche rapide)
• between 8 and 10 km/h → ~8–10 MET (jogging or moderate running for most runners)
• 12–13 km/h → 11–13+ MET (more intense effort, close to fast running)
• above 16 km/h → MET gradually increases, consistent with the Compendium and data on the sports that burn the most calories.

The idea is not to claim that every tenth of a kilometer per hour drastically changes energy expenditure, but to make the result consistent with the scientific literature.

Distance traveled, calories per kilometer and per hour

Based on the race duration (minutes) and speed:

• Distance traveled (km) = speed × duration (h)
• Calories per kilometer = total calories ÷ distance traveled
• Calories per hour = total calories ÷ duration (h)

For most runners, the result is around 0.9–1 kcal per kg of body weight per km traveled, which explains why:

• A person weighing 70 kg often burns ~70 kcal per km.
• and approximately 700 kcal per hour at 10 km/h.

The parameters taken into account in the calculator

The details of each field in the calculator show what is actually changed when the sliders are adjusted.

Weight (kg)

• Body weight (kg) is directly included in the formula MET × kg × hours.
• The higher the body mass (and especially muscle mass), the higher the amount of calories needed to produce the same physical effort increases.

In practice :

• An 80 kg runner will burn more calories than a 60 kg person at the same speed and for the same duration.
• but this is not an "advantage": heavier also means greater strain on the joints and cardiovascular system.

Race duration (minutes)

The duration of the session is the easiest factor to understand: doubling the running time is almost equivalent to doubling the total energy expenditure, at the same speed and under the same conditions.

The expenditure is expressed:

• in total kcal,
• in kcal per hour of running,
• in kcal per minute (useful for comparing with other sports for weight loss such as cycling, elliptical training, swimming, brisk walking, jumping rope, etc.).

Terrain: road, trail, track

The terrain affects the energy cost of running:

• Road (reference): relatively even surface, good energy return with every stride.
• Track: smooth, even surface; a slight reduction factor is applied (slightly more efficient effort, therefore slightly fewer calories per kilometer, all other things being equal).
• Trail running: uneven ground, slopes, roots, rocks, sprints, 3D body management. An energy cost increase factor is applied (more muscle work required for stabilization and propulsion).

Studies show, for example, that very unstable terrain such as soft sand can increase energy expenditure by 40 to 60% compared to a hard surface. For a "classic" trail, the increase is more moderate, but still significant.

Elevation gain (m)

The total elevation gain (m) allows you to factor in the effect of climbs on energy expenditure during a race.

To do this, the ACSM's reference equation for treadmill running is used, which estimates oxygen consumption (VO₂) based on speed and incline (grade):

At a given intensity, the "slope" component accounts for up to +20 to +30% of energy costs for a 5–6% slope.

In the calculator, the average elevation gain (total elevation gain / distance traveled) is used to approximate an average gradient and apply a MET increase factor consistent with these equations.

In other words:

• the greater the elevation gain,
• the more energy expenditure per km increases,
• even if the average speed remains the same.

Temperature (°F)

The body expends energy to maintain a stable internal temperature:

• in very cold weather, it must produce more heat (clothing, shivering, vasoconstriction, etc.);
• In very hot weather, it invests a lot of energy in thermoregulation mechanisms (sweating, vasodilation, increased skin blood flow).

To account for this temperature effect, a moderate coefficient is applied:

• slight increase in estimated expenditure below a certain threshold (severe cold),
• slight increase also above a high temperature (heat).

Wind (km/h)

Running into a strong headwind increases air resistance. This aerodynamic cost increases with the square of the relative speed (runner's speed + headwind). ^Studies³ show that a strong headwind can significantly increase the energy cost of running, by up to 37% for a headwind of 30 km/h.

In practice, a simple approximation is applied:

• the higher the wind speed increases,
• plus a multiplier coefficient slightly inflates the MET.

This is a deliberately simplified model:

• it does not precisely distinguish between headwind and tailwind,
• It does not recalculate air resistance based on the exact speed of the rider plus wind.

Note that under "lambda" conditions (moderate speed, moderate wind), the impact remains moderate.

The aim is to reflect the fact thatjogging at 10 km/h in no wind does not require the same energy as jogging at 10 km/h in a strong headwind, while remaining easy for the user to understand.

Race savings (%): "personal efficiency"

This field allows for differences in "running economy" between individuals to be taken into account, i.e.,the energy efficiency of the running motion.

^Studies456 show that at the same speed:

• Some runners consume significantly less oxygen than others (up to a 30–40% difference) for the same running time.
• which translates into lower calorie expenditure at the same speed.

In the calculator:

• 100% = reference runner (average efficiency),
• < 100 % = coureur moins économique (chaque km coûte un peu plus cher en calories),
• > 100% = more economical runner (same speed, but fewer calories burned).

This allows influence to be reflected:

• training level,
• running technique,
• the type of shoe (e.g., carbon plate shoes),
• body composition (ratio of muscle mass to fat mass).

The results displayed: how to interpret them?

After entering the parameters, the calculator displays several indicators:

Calories burned (kcal)

This is the total estimated expenditure during the running session:

• it includes the incompressible portion related to life (1 MET),
• and the part related to physical activity itself.

To calculate a calorie deficit for the day or week, you can then:

• add this expense to the estimated TDEE (total daily energy expenditure) 
• compare it tothe actualcalorie intake (food).

Distance traveled (km) and pace

The results show:

• the distance traveled calculated from the duration and speed,
• average pace (min/km), useful for comparing sessions and times over 10 km, half marathon, or marathon.

Average MET and intensity level

The calculator displays the adjusted average MET and classifies it on an intensity scale:

• 6–9 MET: moderate to sustained effort (sustained jogging, comfortable running pace);
• 9–11 MET: intense effort for most runners;
• 11–12 MET: very intense, close to competition or structured training.

Officially, recommendations already classify anything above 6 MET as vigorous activity. The more detailed scale used here is therefore an internal scale, intended to help visualize training zones.

Calories per kilometer and per hour

These two indicators are useful for:

• compare running with other endurance sports (cycling, swimming, power walking, downhill skiing, etc.),
• estimate the energy cost of one hour of running at different intensities,
• better understand the effect of pace, terrain, and race duration on calorie deficit.

What the calculator doesn't see (but still matters)

Even when using robust tools (MET Compendium, ACSM equations, orders of magnitude validated by the literature), the result remains an estimate.

Several factors can cause the actual expenditure to vary:

• age,
• sex,
• body composition (muscle mass vs. fat mass),
• state of fatigue,
• stress level and baseline heart rate,
• altitude, dehydration, sleep quality, etc.

Smartwatches and platforms such as Garmin also use models based on heart rate, accelerometer, or GPS. They are not "magical": they also give an estimated figure, which sometimes differs from that of this calculator.

How do I actually use this calculator?

Some ideas for use:

Follow a weight loss goal

• Use the daily calorie requirement calculator + this running calorie expenditure calculator.
• Adjust your diet to create a reasonable calorie deficit (300–500 kcal/day).
• Track changes in weight and waist circumference rather than focusing on a single calorie count.

Optimizing endurance training

• compare different race durations,
• test the impact of average speed or elevation gain,
• See how an hour of trail running compares to an hour on flat ground.

Choosing the right sport to lose weight without injuring yourself

• compare running with power walking, cycling, elliptical training, swimming, etc.,
• Choose a combination of sports activities that allows you to burn calories without exceeding your joint capacity.

In conclusion:

The purpose of this running calorie calculator is not to obsessively count calories, but to provide:

• a scientifically supported estimate of the energy expended during a race,
• the ability to compare different sessions (duration, speed, terrain, elevation gain),
• guidelines for linking training, nutrition, and fitness goals (performance, weight maintenance, fat loss, enjoyment of running).

The figures remain approximations. What really makes the difference in terms of health, body composition, and running progress is:

• regular physical activity,
• a balanced diet tailored to individual needs,
• sufficient sleep,
• and the pleasure of running, week after week.