Calorie Burned Calculator: How Exercise Calorie Estimates Work (2026)

What Is a MET Value?

MET stands for Metabolic Equivalent of Task. It is a standardized unit that compares the energy cost of any physical activity to the energy used sitting quietly at rest. Sitting has a MET value of 1.0 by definition. An activity with a MET of 4.0 requires four times as much energy as sitting.

The Ainsworth Compendium of Physical Activities — first published in Medicine & Science in Sports & Exercisein 1993 and most recently updated in 2011 — catalogues MET values for over 800 activities. It is the foundational reference used by researchers, clinicians, and calculator developers worldwide.

Common MET Values by Activity

Source: Ainsworth BE et al., “2011 Compendium of Physical Activities,” Medicine & Science in Sports & Exercise, 2011.

The Calorie Burn Formula Explained

The standard formula used in calorie burn calculators is:

Calories = MET × weight (kg) × duration (hours)

To convert pounds to kilograms, divide by 2.2. A 155 lb person weighs approximately 70.5 kg.

Example: 155 lb person running at 6 mph (MET 9.8) for 45 minutes (0.75 hours):
Calories = 9.8 × 70.5 × 0.75
Calories = 519 kcal

This is the gross calorie figure — the total energy used including what you would have burned at rest. See the FAQ below for the difference between gross and net calories.

Calories Burned Per Hour for 10 Popular Activities

The table below shows estimated gross calories burned per hour for three common body weights, using MET values from the Ainsworth Compendium. All figures are rounded to the nearest calorie.

The American Council on Exercise (ACE) notes that body weight is the single biggest variable in exercise calorie expenditure — a 185 lb person burns roughly 40% more calories than a 130 lb person during the same workout at the same intensity.

Why Fitness Trackers Get It Wrong

A widely cited 2017 study published in JAMA Internal Medicinetested seven popular wrist-worn fitness trackers (Apple Watch, Fitbit Surge, Basis Peak, Microsoft Band, Mio Alpha, PulseOn, and Samsung Gear S2) against indirect calorimetry — the gold standard for measuring calorie burn.

The results were striking. The most accurate device was still off by 27%. The least accurate overestimated calorie expenditure by 93%. Not a single device met the researchers' threshold for clinical accuracy.

Why the error? Trackers use wrist movement and heart rate as proxies for energy expenditure. But heart rate is affected by caffeine, stress, heat, and dehydration — none of which change actual calorie burn. And wrist movement can't capture the full complexity of activities like cycling, weightlifting, or elliptical training.

The takeaway: treat fitness tracker calorie readouts as rough motivation tools, not precise dietary targets. MET-based calculations, while imperfect, apply a more consistent methodology.

EPOC: The Afterburn Effect

Exercise doesn't stop burning calories when you step off the treadmill. EPOC — Excess Post-exercise Oxygen Consumption — is the elevated oxygen consumption (and thus calorie burn) that continues after a workout as your body recovers, repairs muscle tissue, and restores oxygen stores.

A review in the Journal of Sports Sciences found that high-intensity exercise can produce EPOC effects lasting up to 24 hours post-workout, adding roughly 6–15% to total exercise energy expenditure. Low-intensity steady-state cardio produces minimal EPOC by comparison.

This is one reason HIIT (High-Intensity Interval Training) and resistance training are often recommended for fat loss over pure steady-state cardio — the total calorie cost extends well beyond the session itself.

Activities That Maximize EPOC

• HIIT workouts — alternating near-maximal effort with recovery intervals
• Heavy compound weightlifting — squats, deadlifts, bench press
• Sprint intervals — all-out efforts of 10–30 seconds
• Circuit training — minimal rest between exercises keeps intensity elevated

The American College of Sports Medicine (ACSM) recommends that adults get at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity aerobic activity per week, plus muscle-strengthening activities on 2 or more days per week.

Gross vs Net Calories Burned

Most fitness apps, trackers, and online calculators report gross calories— the total energy used during the activity including your baseline metabolic rate. Net calories subtract the calories you would have burned anyway doing nothing.

For a 155 lb person with a resting metabolic rate of about 1,700 calories per day (roughly 71 calories per hour), a 45-minute run burning 519 gross calories would have a net burn of:

519 − (71 × 0.75) = 519 − 53 = 466 net calories

The difference is modest for most purposes, but it matters if you're trying to calculate precise caloric deficits for weight management. The American Heart Association recommends tracking physical activity as part of an overall approach to heart health that includes diet, sleep, and stress management — not just calorie math alone.

How Body Composition Affects Estimates

MET-based formulas use total body weight, but muscle tissue burns more calories than fat tissue at rest and during exercise. Two people at identical body weights can have significantly different calorie burns if their body compositions differ.

The CDC Physical Activity Guidelines for Americans (2018) acknowledge that exercise calorie estimates are population-level averages and will not perfectly predict any individual's expenditure. Factors like aerobic fitness, muscle mass, age, and heat acclimatization all influence how efficiently the body uses energy.

Experienced runners, for example, tend to burn fewercalories at the same pace than beginners because their movement is more economical — their bodies have adapted to do the same work with less energy. This is why fitness improves over time but makes it harder to maintain the same calorie deficit from the same workout.

Related Guides and Tools

• What is BMR? Basal Metabolic Rate Explained — how your body burns calories at rest
• How to Calculate TDEE and Macros — total daily energy expenditure for weight goals
• Body Fat Percentage Guide — why composition matters more than scale weight
• Pace Calculator Guide — plan running pace and estimate finish times

Frequently Asked Questions

How are calories burned during exercise calculated?

Calories burned are estimated using the MET formula: Calories = MET × weight in kg × hours. MET (Metabolic Equivalent of Task) is a standardized intensity value for each activity. A 155 lb (70 kg) person running at 6 mph (MET 9.8) for 30 minutes burns roughly 343 calories.

Why do fitness trackers overestimate calories burned?

A 2017 JAMA Internal Medicine study found that popular fitness trackers overestimate energy expenditure by 27% to 93%. Trackers use generalized algorithms based on wrist movement and heart rate, which cannot accurately account for individual fitness level, body composition, or exercise efficiency.

What is EPOC or the afterburn effect?

EPOC (Excess Post-exercise Oxygen Consumption) is the elevated calorie burn that continues after intense exercise ends. High-intensity and resistance training can raise metabolism for up to 24 hours post-workout. According to the Journal of Sports Sciences, EPOC can add 6–15% to total exercise energy expenditure.

What is the difference between gross and net calories burned?

Gross calories burned is the total energy used during exercise, including the calories your body would burn at rest. Net calories burned subtracts the resting metabolic rate to show only the calories attributable to the exercise itself. Most fitness apps report gross calories, which is the higher number.

Does body weight affect how many calories you burn?

Yes. Heavier people burn significantly more calories doing the same activity because moving a larger mass requires more energy. A 185 lb person running for 30 minutes burns roughly 30–40% more calories than a 130 lb person at the same pace. This is why the MET formula always includes body weight.

What exercise burns the most calories per hour?

Running at high speeds and vigorous rowing top the list. A 155 lb person running at 8 mph burns approximately 831 calories per hour. Jump rope, cycling at 20+ mph, and high-intensity interval training (HIIT) are also among the highest-calorie activities, all exceeding 700 calories per hour.