### Calculating Miles Per Gallon

· Calculating miles per gallon yourself is easy! We show you how to do it including the formula and also give you a miles per gallon calculator. Home; How many times will I fill up a uhaul truck 40 gal tank 17ft truck and it get 10 miles per gallon going miles. Reply. Tim McMahon says. August 2, 2017 at 2:22 pm.