[McMimmcs]

Originally Posted by Patrick L.

Figuring out fuel mileage ?

Fill tank up where you're comfortable
note odometer reading
drive car
Refill tank at some time again to a point where you're comfortable which should close as to the beginning fill up.
Check odometer reading.
Figure number of gallons vs the miles driven. It'll be close enough for government work.

This is about as simple as you can get! The check isn’t exactly rocket science !