What it is for
Before you hit the road it helps to know what the trip will cost. This calculator estimates the fuel required, the fuel cost, the total with tolls, the cost per person when the bill is split, and the driving time, accepting metric, US and UK units. There is no currency symbol: use your own, as long as the fuel price and tolls are in the same currency.
How the calculation works
Everything is converted internally to kilometers and liters. Constants: 1 mi = 1.609344 km, 1 US gallon = 3.785411784 L, 1 imperial gallon = 4.54609 L. Fuel efficiency becomes km/L: from L/100 km, km/L = 100 ÷ (L/100 km); from US mpg, km/L = mpg × 0.425143707; from UK mpg, km/L = mpg × 0.354006189. Then: liters = distance in km ÷ km/L; fuel cost = liters × price per liter; total = fuel + tolls; per person = total ÷ people; time = distance ÷ average speed.
Worked example
500 km in a 7 L/100 km car needs 35 L. At 6.00 per liter the fuel costs 210.00. Add 40.00 in tolls for a total of 250.00; split between 2 people that is 125.00 each. At 80 km/h the drive takes 6 h 15 min. In US units, 300 mi at 30 mpg and $4.00 per gallon: 300 mi = 482.8 km; 30 mpg = 12.75 km/L; 37.9 L; $1.057 per liter; about $40.0 in fuel.
Tips for good results
Use your car's real-world highway economy (from the dashboard or a full-tank-to-full-tank check) rather than the brochure figure, which tends to be optimistic. For a round trip, add both legs. Average speed should reflect typical highway and city pace but not rest and meal stops, which you can add to the time afterwards.
Limits
This is an estimate: fuel economy varies with speed, terrain, wind, air conditioning, load and driving style, and fuel prices differ from station to station along the way. Wear and tear, parking and lodging are not included.
Frequently asked questions
How do I convert mpg to km/L?
Multiply US mpg by 0.4251 (or UK mpg by 0.3540). The calculator does this for you when you pick the unit.
What is the difference between a US and an imperial gallon?
A US gallon is 3.785 L and an imperial (UK) gallon is 4.546 L, which is why the same car has a higher mpg figure on the imperial scale.
Should the distance include the return trip?
For a round trip, enter the sum of both legs. The calculation uses exactly the distance you type.
Can I use another currency?
Yes. There is no currency symbol; just make sure the fuel price and tolls are in the same currency.