Gas Cost Calculator

Gallons = distance / miles per gallon. Cost = gallons x price per gallon. A round trip simply doubles the distance before anything else is worked out.

How do I work out my real gas mileage?

Fill the tank, reset the trip meter, drive normally, then fill it again. Divide the miles on the meter by the gallons it took. Real mileage is usually a little below the sticker figure, especially in city driving.

Does driving slower actually save gas?

Above about 50 mph, yes, and noticeably. Air resistance rises with the square of speed, so most cars lose 10 to 15 percent of their mileage going from 65 to 75 mph. Under 50 the effect largely disappears.

What else is a trip actually costing?

The IRS mileage rate, around 67 cents a mile, includes tires, maintenance and depreciation as well as fuel. Fuel alone is usually only a third of the true cost of driving a mile.