Fuel Cost Calculator
Estimate how much a trip will cost in fuel: enter the distance, your car’s efficiency and the fuel price to get liters needed, cost per km and the total.
Fill in the distance, your car's efficiency and the fuel price.
How it works
Three inputs, three outputs. From the distance, your car's efficiency (km per liter) and the fuel price per liter, the calculator derives:
- Liters needed = distance ÷ efficiency
- Cost per km = price ÷ efficiency
- Total cost = liters × price
Everything updates as you type. If your car reports consumption as L/100 km instead of km/L, convert with efficiency = 100 ÷ (L/100 km) — for example, 8 L/100 km equals 12.5 km/L.
When to use
Planning a road trip and deciding whether driving beats flying or the bus; splitting fuel fairly among passengers; comparing two routes of different lengths; estimating monthly commute costs (enter your monthly distance); or checking what a fuel price hike does to your budget.
The cost-per-km figure is also the number to use when charging for deliveries or reimbursing work travel by private car.
Practical examples
Weekend road trip
A 420 km trip in a car doing 12.5 km/L with fuel at $1.45/L: 33.6 liters, $48.72 total — about $0.12 per km. Split among 3 friends: $16.24 each.
Monthly commute
44 km per day × 22 working days = 968 km/month. At 11 km/L and $1.50/L, that's 88 liters and $132 a month in fuel alone.
Common mistakes
Using the manufacturer's advertised efficiency instead of your real-world number. Real consumption is typically 10–20% worse than the brochure, especially in city traffic or with a loaded car. For an accurate figure, fill the tank, drive normally, refill, and divide kilometers driven by liters refilled.
Also remember fuel isn't the whole cost of driving: tolls, tire wear, maintenance and depreciation add up. Fuel-only comparisons flatter the car against alternatives like buses or trains.
Frequently asked questions
My car shows L/100 km. How do I convert to km/L?
Divide 100 by the figure: 8 L/100 km = 100 ÷ 8 = 12.5 km/L. (And back: km/L to L/100 km is also 100 ÷ value.)
How do I find my car’s real efficiency?
Fill the tank completely, reset the trip odometer, drive normally until the next full fill-up, then divide the kilometers driven by the liters it took to refill. Repeat over a few tanks for a solid average.
Does the calculator work with miles and gallons?
The math is unit-agnostic as long as you stay consistent: enter distance in miles, efficiency in mpg and price per gallon, and the outputs become dollars total and cost per mile.
How should passengers split fuel costs?
The simplest fair split is total fuel cost divided by the number of people including the driver. Some groups add a share for vehicle wear — a common convention is fuel cost plus 20–30%.