Flights climbed - apple watch counting too many (way too many)

See if this helps...https://support.apple.com/en-us/HT207941

Try resetting your Watch by pressing in the crown and side button until you see the Apple logo.

I just think that the altimeter in Apple watches does not work very well. When I do an outside walk which should have only about a ten foot rise, it records 37 feet. But when I go up and down the stairs in my two story house all day, it rarely records more that 1 or 2 flights. I don't think there is anything you can do about it. Perhaps Apple will be able to fix this bug in a future software upgrade.

The recommended support article doesn't help at all for me: the watch series 4 does measure heart rate, steps, etc. accurately but it simply counts too many flights as of months now. It runs the latest software, it has been restarted, I continuously capture work outs on flat surface. But it is just reporting an excessive amount of flights (100+) day in day out since months. I am quite happy with the watch but I don't like the fact that it is off so much on the flights metric. I live in a flat country (there is hardly any elevation difference) and a climb about 10-20 flights a day which doesn't justify a number over 400. The count is 45 this morning and I only climbed/ascended the stairs in my house 4 times.....

And it did work the first months.

Main difference in my case: I have changed from a woven nylon band to a metal milanese band a few months ago.

Could that be a potential root cause?

Interesting. I have just the opposite problem. It only counts half the flights.

How many steps does your stairs have?

13 for 3m (10 feet) height which should be 1 flight. Note it also counts flights when I don't take the stairs.