It varies from 3 meters up to 30 meters depending on where you are
It varies from the Dead Sea (403 metres below sea level, it's the lowest place on Earth) to quite high mountains. Sorry, neither of the atlases in front of me quotes the highest.
It is 48 feet above sea level.
The Glasgow-Bishopton weather station is 59 metres above sea level.
Bacup, Lancashire? 257 metres
Its altitude is 3,490 metres or 11,450 feet above sea level.