Calories Burned

How Exercise Calorie Burn Is Calculated

Calories burned during exercise is estimated from an activity’s MET value — how many times your resting metabolic rate that activity burns — multiplied by your body weight and how long you did it. Pick an activity, enter your weight and duration, and this calculator estimates the calories burned instantly.

MET (Metabolic Equivalent of Task) values come from the Compendium of Physical Activities, a long-standing reference exercise physiologists and researchers use to standardize activity intensity across studies. A MET of 1 is roughly the energy cost of sitting quietly; an activity with a MET of 8 burns about 8 times that.

The Formula

$$\text{Calories Burned} = \vA{\text{MET}} \times \vB{\text{Weight (kg)}} \times \vC{\text{Duration (hours)}}$$

Worked Example

A 70 kg (154 lb) person running at 6 mph (a 10-minute mile pace, MET 9.8) for 30 minutes:

1. Convert duration to hours: $30 \div 60 = 0.5$ hours.
2. Calories: $\vA{9.8} \times \vB{70} \times \vC{0.5} = 343$ calories.

Key Factors to Consider

• A higher-weight person burns more calories doing the same activity than a lower-weight person. Since the MET formula multiplies directly by body weight, two people doing the exact same activity for the exact same duration will get different calorie estimates if they weigh different amounts — this is expected, not an error.
• Terrain, incline, and intensity within an activity all shift the true MET value. A MET table typically lists a specific pace or intensity for each activity (e.g. “running, 6 mph”) — running uphill, at a faster pace, or with added resistance burns more than the flat, moderate-pace MET value the table lists, so pick the entry closest to your actual effort level.
• This estimates exercise calories only, not your total daily burn. Calories burned from everyday activity (walking around, fidgeting, digestion) and your body’s baseline resting burn are separate from this exercise-specific estimate — see the Calorie/TDEE Calculator for a full-day estimate that includes all of that.
• A fitness tracker with a heart-rate sensor generally estimates more precisely for a specific individual. MET tables are population averages; a heart-rate-based estimate is personalized to your own current heart rate during the activity, which correlates more directly with your actual effort than a fixed table value does.

Interpreting Your Results

A single workout’s calorie estimate is most useful in context, not as a standalone number. If you’re weighing it against food, a commonly-cited rule of thumb is that roughly 3,500 calories correspond to about one pound of body fat — so a 350-calorie workout is a small, steady piece of a much bigger weekly picture, not something to “earn back” with an extra snack the same day. Pair this result with the Calorie / TDEE Calculator to see how a day’s exercise fits alongside your total daily energy needs, rather than treating the exercise number in isolation.

It’s also worth comparing the estimate across a few different activities or durations rather than trusting one single result too precisely — if two different activities in the table produce very similar numbers for the same time and weight, that’s a sign that either would have a broadly similar effect on your day’s energy balance, even if the exact figures differ by a little.

A Note on Accuracy

MET-based estimates are averages across many people at a given activity intensity — they don’t account for individual fitness level, effort, terrain, or body composition, so your actual calorie burn can vary meaningfully from the estimate. Use this as a general planning figure, not a precise measurement.

Useful to Know

MET-based calculations like this one estimate your total (gross) energy expenditure during the activity — including the calories your body would have burned anyway just staying alive during that time — not only the extra calories the activity itself adds on top of resting. This is why even very light activity never shows as zero calories: sitting still already has a MET of about 1. If you’ve seen a different number described as “net calories burned,” it was likely calculated by subtracting your estimated resting burn first, which is a related but distinct figure from the gross estimate this calculator reports.