Fuel Cost Calculator

If you think in miles, mpg and dollars per gallon, switch the "Unit system" selector to US gallons — no manual conversion needed. Enter four numbers and press Calculate:

1. Trip distance in kilometers or miles, depending on the unit system you picked (one way; double it for a round trip). 2. Average consumption in liters per 100 km, or your car's mpg in gallon mode. A 30-mpg sedan burns about 7.8 L/100km. 3. Price at the pump, per liter or per gallon to match your selection. 4. People splitting the cost, so everyone pays the same share.

The formula the calculator runs, in plain text:

liters = distance x consumption / 100 total cost = liters x price per liter cost per person = total cost / people

Worked example with the defaults: 400 km x 6.5 L/100km / 100 = 26 liters; 26 x $1.60 = $41.60 total, which for a solo driver is also $41.60 per person.

Two friends drive from Los Angeles to Las Vegas on I-15: about 270 miles, which is roughly 435 km. Their midsize sedan averages 28 mpg on the highway — converting, 235.215 / 28 = 8.4 L/100km. Gas along the route costs $3.60 per gallon, which is 3.60 / 3.785 = about $0.95 per liter.

Step by step: 435 x 8.4 / 100 = 36.54 liters (about 9.7 gallons). Multiply by the price: 36.54 x 0.95 = $34.71 for the one-way drive. Split two ways, that is 34.71 / 2 = $17.36 each — cheaper than most rideshare trips across town.

For the drive home, just double everything: about $69.43 total and $34.71 per person for the whole weekend. Note that this is fuel only; parking on the Strip is a separate line item. In a 22-mpg SUV (10.7 L/100km) the same one-way leg would run about $44.21, almost ten dollars more.

The consumption figure you enter is not fixed — it depends on how you drive. These habits make a real difference on a long American road trip:

• Tire pressure: check it cold before you leave. Running a few psi low can add roughly 2-4 % to consumption and wears the tires faster.
• Steady, moderate speed: pushing from 65 to 80 mph sharply increases aerodynamic drag and can burn 15-20 % more fuel. Cruise control pays for itself on the interstate.
• Look ahead: coasting toward a red light instead of braking late saves both gas and brake pads.
• Weight and aerodynamics: empty the trunk and remove the roof box or bike rack when unused — at highway speed a roof box can add 10-20 % to consumption.
• Shop around: gas price apps routinely show differences of 30-50 cents per gallon within the same city.

mpg vs. L/100km, demystified. American cars measure efficiency in miles per gallon, while this calculator uses liters per 100 km. The two scales are inverses of each other and the bridge is one constant: 235.215. To convert either way, divide 235.215 by the number you have. So 30 mpg = 235.215 / 30 = 7.84 L/100km, and 6.5 L/100km = 235.215 / 6.5 = 36.2 mpg. For the pump price, divide dollars per gallon by 3.785 to get dollars per liter.

Treat the result as an estimate: traffic, terrain, A/C and cargo can swing real-world consumption by 10-15 % either way.

This calculator tells you in seconds how many liters (or gallons) you will burn, what that means in dollars, and how much each person owes when you split the bill. All you need are three numbers you already have: the distance, your car's average consumption, and the price at the pump. If your car reports mpg, the guide below shows the 10-second conversion.