Meetre calculates distances betweem two points instantly.
It uses your smart device's GPS sensor to obtain the positions.
If you open your internet connection, the results will be more precise.

Usage:
Go to origin point and press the button once.
Go to destination point and press the button again. The distance will be shown to you.
You don't need to keep your device or application (also GPS and Internet) open while going from the origin point to destination point.