How Does Your Garmin Know You've Climbed a Floor?

Day 9: The Barometric Altimeter

"How does your Garmin watch know how many floors you've climbed?"

This one surprises a lot of people. GPS can tell you your altitude, but it's not accurate enough (or fast enough) to detect a single floor. Garmin uses a completely different approach.

The barometric altimeter

Air pressure decreases as you go higher. This happens on a large scale (mountains vs sea level) but also on a very small scale — climbing one flight of stairs changes the air pressure around you by a measurable amount.

Garmin watches with a barometric altimeter contain a tiny pressure sensor. When you climb roughly 10 feet (3 metres) in elevation, the watch registers one floor.

Why it sometimes gets it wrong

• Elevators: Fast pressure change = floors counted, even though you didn't climb
• Weather changes: Atmospheric pressure changes with weather. The watch recalibrates regularly but can drift
• Riding in a car: Going up a hill counts floors even without stairs

How to check if your Garmin has a barometric sensor

Not all Garmin models include a barometric altimeter. Check your model's spec page on garmin.com. Entry-level models (Forerunner 55, Vivoactive) often use GPS altitude instead — which is far less accurate for floor counting.

If accurate floor counting matters to you (you climb a lot of stairs at work), make sure your Garmin has a barometric altimeter before buying.