How does Garmin calculate calories?

Garmin combines two things. First, your basal or resting burn, estimated from your age, sex, height, and weight, which is the energy you use just staying alive. Second, your active burn, estimated mostly from your heart rate during movement. Together they make your daily total.

What's the difference between active and total calories?

Total calories include everything, most of which is your passive resting burn that happens whether you move or not. Active calories are just the extra you burn through movement and exercise. For most people the passive share is the larger of the two.

Why are my calories only tracked when I wear the watch?

The active portion depends on your heart rate and motion, which the watch can only read while you are wearing it. Take it off and Garmin has to fall back on your baseline burn, so a chunk of your active calories goes uncounted.

Are Garmin calories accurate?

They are a reasonable estimate, not a precise measurement. Because the active portion leans on heart rate, activities with high effort but low heart rate, like heavy strength training, can under-read. Use the number as a consistent trend rather than an exact figure.

How does Zenith use calories?

Zenith reads the calories your Garmin records and uses them as part of your activity picture. The more meaningful training signal for how hard a session taxed you is strain, which weighs intensity rather than raw energy burned.

Calories, Explained | Zenith Wellness

Calories explained

The calorie number looks simple, but under the hood it is really two different things added together. Knowing the split makes the number a lot more useful, and a lot less mysterious.

Quick answer: Your daily calories are your passive burn (the energy you use just being alive, from your age, sex, height, and weight) plus your active burn (the extra from movement, estimated from your heart rate). Most of your total is passive. Garmin’s number is a solid estimate, not an exact measurement.

The two halves of your burn

Passive burn, also called your basal metabolic rate, is what your body spends keeping you alive: your heart beating, your brain running, your cells doing their work. It happens whether you move or not, and for most people it is the bigger share of the daily total. Garmin estimates it from your age, sex, height, and weight.

Active burn is the extra you spend moving, from a walk to a workout. Garmin estimates it mostly from your heart rate: the higher your heart rate climbs during activity, the more calories it attributes to the effort.

Add the two and you get the number on your watch.

Why it is only tracked with the watch on

Your passive burn ticks along regardless, but the active portion needs your heart rate and motion, and the watch can only see those while you wear it. Take it off during a workout and that effort largely goes uncounted. This is why coverage matters if you care about the total.

Why it is an estimate

Because active calories lean on heart rate, the number is only as good as that proxy. Steady cardio, where heart rate tracks effort well, reads accurately. Heavy strength training is trickier: the effort is high but heart rate often stays moderate, so calorie estimates can come in low relative to how hard the session felt. Treat the figure as a consistent trend to compare against itself, not a precise count.

How Zenith uses it

Zenith reads the calories your Garmin records as part of your activity picture. For judging how hard a session taxed your body, though, the sharper signal is strain, which weighs intensity rather than raw energy, and pairs with active time to describe your day.

To see your activity and strain read from your Garmin, try Zenith. It’s free to start.