A typical day for an adult burns somewhere between 1,800 and 3,000 calories in total. If your app shows 8,000, 14,000 or any number that would make you an ultramarathon runner, your watch isn't broken. It's a mix-up between two numbers with similar names and very different meanings.
Active calories and total calories
- Active calories: what you burned ON TOP of your baseline because you moved. This is the number that makes sense next to a workout.
- Total calories: active calories plus what your body burns just to keep running - breathing, pumping blood, holding its temperature. That baseline burn is the biggest part of the day for almost everyone.
Garmin and Fitbit report the total, with the baseline built in. That's correct from their point of view: it's what you actually burned that day. The error happens one step later, when another app reads that number as if it were exercise alone.
Where the math blows up
There are two ways the number gets inflated, and they add up.
The first is counting the baseline twice. If the app adds up the day's total calories and then adds each workout on top, the baseline goes in twice. A 2,400-calorie day becomes 4,000 without anything unusual happening.
The second is quieter: overlapping intervals. The watch records blocks of energy burned throughout the day, and sometimes those blocks overlap - an hourly block and another one for the workout that happened inside that hour. An app that simply adds everything up counts the same stretch of time two or three times. That's how you get to 14,000.
How to tell if this is your case
- 1Write down the calories your watch's own app shows for yesterday - in Garmin Connect or in Fitbit.
- 2Write down what the other app shows for the same day.
- 3Compare.
If the second number is close to the first, you're fine - both are talking about total burn. If the second one is much higher, something is being counted twice. And if the second one is close to the watch's total but labeled as exercise or activity, the label is wrong, even if the number is right.
A quick reference point: an adult's baseline burn is roughly 1,400 to 1,900 calories a day. If you subtract that from what the app shows and what's left doesn't look like your day, the number is wrong.
Why this matters more than it seems
If you use this number to decide how much to eat, you're deciding based on math that's off - and off on the high side. An app that says you burned 4,000 calories suggests you can eat 4,000, and the gap between that and reality is a deficit that never happens, or a surplus no one can explain.
And in Biomapa
Biomapa went through exactly this. Garmin users were showing up with days of more than 14,000 calories, and the cause was both of the things described above. Today the app separates baseline burn from activity burn, removes the overlap between intervals and shows each one under the right name. When the watch only provides the total, Biomapa says it's the total - instead of calling it exercise.