Whether you are trying to lose weight, train for a race, or simply understand what your weekend hike actually cost you, the question is always the same: how many calories did that activity burn? This calorie burn calculator uses the standard MET (Metabolic Equivalent of Task) equation to estimate the kilocalories you burn during any activity, from a slow walk to a hard interval session. Adjust your weight, pick the activity intensity, and enter your duration — the result updates instantly so you can compare running, cycling, swimming, or gardening side by side.
How to Use
- Enter your Your Weight in kilograms. The heavier you are, the more energy every movement costs, so this is one of the two biggest drivers of the result.
- Set the Activity MET Value. MET is the ratio of the energy you use during an activity to the energy you use sitting still. Resting is 1.0; light walking is about 3.5; cycling at a moderate pace is about 7.5; jogging at 8 km/h is about 8.3; fast laps in the pool are about 10.0. If you are unsure, the Compendium of Physical Activities lists MET values for hundreds of activities.
- Enter the Duration in minutes. Even a modest activity adds up: 30 minutes a day, five days a week, is 130 hours a year.
- Read the result card. Calories Burned is the headline number for the session; Calories per Hour lets you compare activities fairly regardless of how long you exercised; Equivalent Fat Burned converts the session into pounds of body fat using the common 3,500 kcal-per-pound rule of thumb.
The estimate is a gross figure — it includes the calories you would have burned anyway just by sitting. To isolate the extra calories from exercise, subtract one MET from your activity value before calculating.
The MET Formula
This calculator applies the equation used by exercise physiologists around the world:
kcal = MET × body weight (kg) × duration (hours)
A MET of 1.0 represents your resting metabolic rate — roughly the energy you spend awake and motionless. Every additional MET means you are working that much harder. For a 70 kg person running for 30 minutes at a MET of 8.3:
- Hours = 30 ÷ 60 = 0.5
- kcal = 8.3 × 70 × 0.5 = 290.5 kcal
That works out to a burn rate of 581 kcal per hour. The same person walking (MET 3.5) for the same 30 minutes burns only about 122.5 kcal, which is why intensity changes the result far more than small tweaks in duration.
Choosing the Right MET
Picking a realistic MET is what makes the estimate trustworthy. Use this quick reference:
- 1.0–2.0 — sleeping, sitting at a desk, slow typing.
- 2.5–3.5 — slow walking on level ground, light housework, stretching.
- 4.0–6.0 — brisk walking (about 5.5–6 km/h), easy cycling, doubles tennis.
- 6.0–9.0 — jogging 8 km/h, moderate cycling, swimming leisurely, hiking uphill.
- 9.0–12.0 — running 10 km/h, vigorous lap swimming, circuit training, singles tennis.
If your heart rate is sitting near 70% of your estimated maximum, a MET around 6–8 is usually realistic; if you cannot hold a conversation, you are likely above 9.
Examples
Example 1 — A 70 kg runner jogs for 30 minutes at 8 km/h (MET 8.3). Duration is 0.5 hours, so calories burned = 8.3 × 70 × 0.5 = 290.5 kcal, at a rate of 581 kcal per hour. That is roughly the energy in a slice of pepperoni pizza.
Example 2 — An 80 kg person walks briskly for 60 minutes (MET 3.5). Calories burned = 3.5 × 80 × 1.0 = 280 kcal. Even though the intensity is low, the full hour of duration nearly matches the runner's shorter, harder session.
Example 3 — A 60 kg swims laps for 45 minutes (MET 10.0). Hours = 0.75, so calories burned = 10.0 × 60 × 0.75 = 450 kcal — the equivalent of about 0.13 lb of body fat under the 3,500 kcal rule.
FAQ
How many calories do I burn in a 30-minute run?
For a 70 kg person jogging at about 8 km/h (MET 8.3), 30 minutes burns roughly 290 kcal. Heavier runners burn more — an 80 kg runner at the same pace burns about 332 kcal — while lighter runners burn less.
What does MET stand for?
MET stands for Metabolic Equivalent of Task. One MET is the energy you use while sitting quietly, roughly 1 kcal per kilogram of body weight per hour. An activity rated at 5 MET uses five times the energy of sitting.
Is the 3,500 kcal per pound rule accurate?
It is a useful rule of thumb, not a law of nature. Real weight loss responds to diet, hormones, and adaptation, so treat the equivalent-fat number as an estimate. Many people find that exercise alone without a small calorie deficit changes the scale far slower than the 3,500 kcal rule predicts.
Does a heavier person burn more calories exercising?
Yes. Because the formula multiplies by body weight in kilograms, a 90 kg person doing the same activity at the same intensity burns about 29% more than a 70 kg person. Extra body mass literally means more work to move.
What is the difference between gross and net calories burned?
This calculator shows gross calories, which includes the resting energy you would have burned anyway. Net exercise calories remove that baseline: use (MET − 1) instead of MET when you want to count only the extra benefit of the workout.
How many calories does walking burn?
A 70 kg person walking at a brisk pace (MET 3.5) burns about 245 kcal per hour. A slower stroll (MET 2.5) burns about 175 kcal per hour for the same person. Longer, slower walks can rival shorter runs for total energy expenditure.
Disclaimer
This calorie burn calculator is provided for informational purposes only and is not medical advice. Estimates are based on the MET formula and population averages; actual energy expenditure varies with fitness, terrain, genetics, age, and body composition. Do not use these numbers to set a medical, dietary, or training plan without consulting a qualified doctor or registered dietitian. Smekys makes no guarantee of accuracy and is not liable for decisions made based on these estimates.