Calories Burned Calculator: MET Formula & Exercise Guide

The Calorie Burn Formula

The standard method for estimating calories burned during exercise uses MET values:

Calories = MET × Weight (kg) × Time (hours)

MET stands for Metabolic Equivalent of Task. It's a ratio that compares an activity's energy cost to your resting metabolic rate. One MET equals the energy your body burns while sitting quietly — roughly 1 kcal per kilogram of body weight per hour.

An activity rated at 4 MET means your body is burning energy at four times its resting rate. At 10 MET, ten times. The formula is simple but surprisingly accurate when you use the right MET values.

What Is MET?

MET values are published by the Compendium of Physical Activities, a research database maintained by exercise scientists. The compendium assigns MET values to hundreds of activities based on measured oxygen consumption.

One MET = energy at rest. Four MET = four times resting metabolic rate. The higher the MET, the more intense the activity and the more calories you burn per minute.

Here's how common activities compare:

Notice that sleeping comes in below 1 MET — your body burns slightly fewer calories lying still than sitting upright. And HIIT can reach 14 MET, meaning your body is working 14 times harder than at rest.

Worked Example: 45-Minute Run

Let's calculate calories burned for a 70 kg person running at 6 mph for 45 minutes.

Running at 6 mph has a MET value of 9.8. Forty-five minutes is 0.75 hours.

Calories = 9.8 × 70 × 0.75 = 514.5 kcal

That's about half a pound of fat equivalent in a single run. Now run three times a week and you're looking at 1,500+ calories of exercise deficit — roughly a pound of fat per week if diet stays constant.

The math is straightforward. The hard part is consistency. Use our calories burned calculator to find your numbers for any activity.

How Body Weight Affects Calorie Burn

Weight is directly proportional to calories burned. A heavier person burns more calories doing the same activity for the same duration because they're moving more mass against gravity and resistance.

A 90 kg person burns 50% more calories than a 60 kg person doing the same workout. This is also why calorie burn decreases as you lose weight — your body is lighter, so each workout burns fewer calories. Adjust your exercise volume or intensity as you progress.

The Afterburn Effect (EPOC)

High-intensity exercise doesn't just burn calories during the workout. It triggers EPOC— Excess Post-Exercise Oxygen Consumption — sometimes called the afterburn effect.

After intense exercise, your body works to restore oxygen levels, repair muscle tissue, and return to homeostasis. This process consumes extra energy for 24–48 hours after the workout. Studies suggest EPOC can add 6–15% to the total caloric cost of a vigorous session.

That's not a massive number, but it adds up. A hard 45-minute HIIT session that burns 500 calories during the workout might burn another 50–75 calories in the recovery window.

Low-intensity exercise like walking produces minimal EPOC. Zone 2 cardio (more on that below) produces moderate EPOC. HIIT and heavy strength training produce the most. If afterburn matters to you, intensity is the lever to pull.

Zone 2 Training and Fat Burning

Not all exercise is created equal for fat oxidation. Zone 2 training — sustained effort at 60–70% of your maximum heart rate — is where your body preferentially burns fat as fuel.

At higher intensities, your body shifts toward burning carbohydrates (glycogen) because they can be metabolized faster. At Zone 2, the pace is sustainable enough that fat oxidation dominates.

This doesn't mean Zone 2 burns more total calories than HIIT — it doesn't. But for endurance athletes, metabolic health, and long-duration sessions, Zone 2 is highly effective. A 90-minute Zone 2 ride or jog can burn 600–900 calories with relatively low recovery cost.

For most people, the best approach combines both: Zone 2 for volume and metabolic health, higher-intensity work for cardiovascular fitness and EPOC.

Why You Can't Out-Exercise a Bad Diet

Running one mile burns roughly 100 calories. That's about one medium cookie. Or a small handful of nuts. Or a quarter of a standard candy bar.

Exercise is essential for health. But as a calorie-burning tool, it's surprisingly inefficient compared to dietary changes. Cutting 500 calories from your daily diet is far easier than burning 500 extra calories through exercise.

The CDC recommends 150 minutes of moderate-intensity aerobic activity or 75 minutes of vigorous-intensity activity per week for substantial health benefits — plus muscle-strengthening activities on 2 or more days. That's a reasonable target for health, not necessarily weight loss.

For weight management, the research is clear: diet controls the majority of the caloric equation. Exercise controls a smaller portion but contributes enormously to metabolic health, cardiovascular fitness, mood, and longevity. Think of exercise as non-negotiable for health, not as permission to eat more.

Fitness Tracker Accuracy

Fitness trackers are convenient but not precise. A 2017 Stanford study evaluated seven popular wearable devices and found that all of them overestimated calorie burn. The range of error was 27–93%.

The Apple Watch performed best at around 27% error. The PulseOn was worst at 93%. No device came within 10% accuracy for energy expenditure.

Heart rate measurement was more accurate — most devices got that right. But translating heart rate to calories is where the errors compound. Individual variation in fitness level, body composition, and exercise efficiency all affect the actual calorie burn, and most algorithms don't account for these well.

Use tracker estimates as trends, not absolutes. If your watch says you burned 400 calories on a run, the real number might be anywhere from 215 to 510. The MET formula gives you a more grounded estimate when you know your weight and activity duration.

Frequently Asked Questions

How do you calculate calories burned during exercise?

Multiply MET × body weight in kg × duration in hours. MET (Metabolic Equivalent of Task) is a standard measure of exercise intensity. For example, a 70 kg person running at 6 mph (MET 9.8) for 45 minutes burns approximately 9.8 × 70 × 0.75 = 514.5 kcal. Our calories burned calculator handles this automatically for dozens of activities.

What is MET value in exercise?

MET stands for Metabolic Equivalent of Task. One MET equals the energy your body burns at rest — roughly 1 kcal per kg per hour. An activity with a MET of 4 means your body is working at 4 times its resting metabolic rate. Walking at 3 mph has a MET of about 3.5; running at 6 mph has a MET of about 9.8. The higher the MET, the more intense the activity.

How many calories does running burn per mile?

Running burns roughly 80–140 calories per mile depending on body weight and pace. A common rule of thumb is about 100 calories per mile for a 70 kg (154 lb) person. Heavier runners burn more; lighter runners burn less. Pace affects calorie burn less than most people expect — faster running burns more calories per minute but fewer per mile, since you cover the distance quicker.

Do heavier people burn more calories?

Yes. The MET formula multiplies by body weight, so a heavier person burns more calories doing the same activity for the same duration. A 90 kg person running for 30 minutes burns roughly 29% more calories than a 70 kg person at the same pace. This is because moving more mass requires more energy. It also means calorie burn gradually decreases as you lose weight, so you may need to increase workout duration or intensity to maintain the same deficit.

How accurate are fitness trackers at measuring calories burned?

Not very accurate. A 2017 Stanford study found that popular fitness trackers overestimated calorie burn by 27–93%. The Apple Watch was the most accurate (27% error); the PulseOn was the least (93% error). No device tested was accurate within 10%. Heart rate tracking was more reliable, but converting heart rate to calories introduces significant individual variation. Use tracker estimates as rough directional guides, not precise measurements.