How do you measure the strength or power of a magnet?
Gaussmeters, magnetometers or pull testers are most commonly used to measure the strength of a magnet. Gaussmeters measure strength in gauss; magnetometers measure in gauss or arbitrary units (which makes it easy to compare one magnet with another); pull testers measure pull in pounds, kilograms or other units of force. Helmholtz coils, search coils and permeameters are also used for sophisticated magnet measurements.
Specialized gaussmeters can cost up to several thousand euros.