How to Calculate Calories Burned in a Workout

Ever look at your fitness watch after a workout and wonder where that calorie number came from? Most calorie-burn estimates, whether from an app, a watch, or a printed chart, start from a simple science idea called a MET. Once you understand the MET formula, you can calculate calories burned in a workout for almost any activity, using just your body weight and how long you moved.

What Is a MET and Why It Matters

MET stands for metabolic equivalent of task. It compares how much energy an activity uses to the energy you use just sitting still. Sitting quietly counts as 1 MET, which is your resting baseline.

A more intense activity gets a higher MET score. Walking at a normal pace is about 4 MET. Jogging is about 7 MET. Fast running can reach 10 MET or higher, so it burns calories much faster than walking.

Researchers built MET values by measuring oxygen use during many activities, then averaging results across many people. That is why MET numbers make useful general guides, not an exact match for your body. The CDC keeps a public page on measuring physical activity intensity that explains this scale in more detail.

The Formula for Calories Burned During Exercise

Once you know an activity’s MET value, a simple formula turns it into calories. The most common version works like this:

Calories per minute = MET x 3.5 x your weight in kg / 200.

Multiply that per-minute number by your workout time in minutes to get your total burn. A simpler shortcut also gets you close: calories = MET x your weight in kg x hours of exercise.

Both formulas give an estimate, not a lab-measured reading. They rely on average oxygen data, so your true burn depends on your fitness level, your effort, and your body. Still, they are a solid starting point for comparing activities or planning a session.

Worked Example: Jogging for 30 Minutes

Here is the precise per-minute formula in action, using a 70 kg (about 154 lb) person jogging at MET 7 for 30 minutes.

1. Multiply MET by 3.5 by body weight in kg: 7 x 3.5 x 70 = 1,715.
2. Divide that result by 200: 1,715 / 200 = 8.575 calories per minute.
3. Multiply by workout minutes: 8.575 x 30 = about 257 calories.

So this 30-minute jog burns roughly 257 calories, using the precise formula. The quick shortcut (MET x kg x hours) gives 7 x 70 x 0.5 = 245 calories, a close but slightly different number.

Neither answer is wrong. Both are reasonable estimates built from the same MET idea, not a lab-measured exact count for your body.

Calories Burned Per Hour for Common Activities

Different activities burn calories at very different rates, based on their MET value. The chart below shows rough hourly totals for a 70 kg (154 lb) person doing four common activities at a steady pace.

These numbers assume one hour of steady effort at each activity’s typical MET value. A heavier body generally burns more calories at the same MET, because the formula multiplies by body weight.

Wearables vs Formula: Comparing Two Estimates

Fitness watches and formula-based math often land in the same ballpark, but they rarely match exactly. A wearable also runs a formula, blended with your heart rate and sometimes your motion data, so its estimate can shift as you move.

For the 30-minute jog example above, a wearable might report about 268 calories from heart-rate data. The plain MET formula gives about 257 calories for the same jog.

Neither number is wrong. Both are estimates built from different data and different assumptions about your body. Use either one as a helpful guide for tracking effort over time, not as an exact calorie count.

How Heart-Rate-Based Estimates Work

Heart rate is another common way to estimate calories burned, separate from the MET formula. This method assumes a higher heart rate roughly means higher effort, and higher effort means more calories used per minute.

Heart-rate math typically uses your age, sex, weight, and average heart rate during exercise to estimate effort. It skips MET values entirely, which is why it can disagree with a MET-based estimate for the exact same workout.

Heart rate also reacts to things that are not really effort, like heat, dehydration, caffeine, stress, and poor sleep. Any of these can push your heart rate up without raising your true calorie burn by the same amount. That is one more reason heart-rate estimates can be off by a meaningful margin, just like MET-based math.

What Changes Your Real Calorie Burn

Several real factors push your true burn above or below any formula estimate. These are the biggest ones to keep in mind:

• Fitness level: a trained body often moves more efficiently, burning slightly fewer calories at the same pace.
• Effort: pushing harder, like adding hills or speed, raises your MET and your total burn.
• Terrain and conditions: hills, wind, heat, and soft ground all raise the effort of the same activity.
• Muscle mass: more muscle tends to raise both resting and active calorie burn.
• Body weight: heavier bodies burn more calories doing the same activity, since weight is part of the formula.

Body weight has an outsized effect because it is multiplied directly into the formula. Doubling body weight roughly doubles the estimated burn for the same MET and duration, even though real physiology is more complex than one formula can fully capture.

These factors are why two people can do an identical workout and burn a different number of calories. Treat any calorie estimate as a helpful range, not a fixed number.

Afterburn: Calories Burned After Your Workout Ends

Your body keeps burning some extra calories after a hard workout ends, an effect called excess post-exercise oxygen consumption, or EPOC. Recovery uses energy to restore oxygen levels, cool the body, and repair muscle tissue.

This afterburn effect is real, but it is usually a modest add-on rather than a dramatic extra total. It tends to run higher after intense or long efforts than after light, easy sessions.

The formulas and wearable estimates in this guide cover the workout itself. They generally do not include afterburn, so your true total calorie cost may run a little higher than either estimate shows.

Workout Calories vs Daily Maintenance Calories

The calories you burn in one workout differ from your daily maintenance calories, the total energy your body uses across a full day, including rest. Workout calories are just one slice of that bigger daily total.

If you want to understand your full daily energy needs, see our guide on How to Calculate Your Maintenance Calories.

Using the Exercise Calorie Calculator

Doing this math by hand works, but it takes a few steps every time you want a new estimate. Our Exercise Calorie Calculator runs the MET formula for you.

Enter your weight, pick an activity, and set your workout time. The tool returns an estimated calorie burn in seconds, using the same MET-based math shown above.

Frequently Asked Questions About Calories Burned in a Workout

Sources

This article is for general education only, not medical advice. Nutrition needs vary by person, so talk with a doctor or a registered dietitian before making changes to your diet or health routine. Reviewed for accuracy by Dr. Abdullah Khalil, MBBS. Last updated September 12, 2026.