To... itself? Go measure something. You now have a reference!
If you scratch out the labels of your car speedometer and forget which is which, it still measures speed. 80 is still 33% faster than 60, regardless of the units.
I suspect your questions would be answered better by playing around with the tool in question for a few minutes anyway, as you seem to be asking about capabilities the tool does not purport to have.
If you scratch out the labels of your car speedometer and forget which is which, it still measures speed. 80 is still 33% faster than 60, regardless of the units.