Garmin calorie estimator

Hey y’all.

Curious if anyone that wears a garmin watch has any clue how they derive their calorie burn numbers. I understand the BMR measurement but the active calorie burn is a bit perplexing. My own thoughts would be BMR + calories burned from kJ work from power meter + overall active calories from day to day stuff. Seems simple enough. The watch however will get the data from a workout and then immediately “discredit” some of the calories from that effort. For example a 1200cal ride may only show up as 1050 active calories on garmin connect.

Is garmin suggesting that a portion of my 1200cal work is attributable to BMR burn? If that’s the case I can’t really wrap my head around it.

Just seeing if anyone has any insight

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In my experience, the Garmin calorie counting doesn’t give you full credit for calories from workouts if you do them earlier in the day because it’s waiting to see if you hit your steps target for the day … then by the end of the day it tends to reconcile as you’d expect. That’s my observation from doing power-based workouts on a turbo that get uploaded to Garmin Connect, which in turn syncs with my Forerunner 35 watch (which is doing the step counting).

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Ive got a Garmin watch but I dont really pay attention to it calorie calculator. I wouldn’t be surprised if it was off for a workout, it always under reads the HR, eg during today it has recorded a max of 131bpm but my chest strap recorded a max of 175bpm for tonight’s workout. Yesterday the difference was even more 139bpm on the watch v 190bpm of the strap :exploding_head:

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I just upgraded but still don’t wear my garmin 24/7 so I haven’t paid attention to the calories metrics on the watch or what it shows in the connect app for the day. However I have noticed that when I manually enter a swim the calories show up different when I enter an identical workout in the app vs via the browser. At first I thought it was maybe just a glitch in their algorithm like weighting a 45 minute swim more than 44 so I deleted the app one one day and entered it online and it was different, same distance, same duration, same start time. We’re talking like 500 in one and 750 in another, so not a small difference.

I’ve got little faith in their calorie tracking because of this and just ignore it.


Surely the basal metabolic calories are subtracted when Garmin adds the sport calories?