Fuel Cost Calculator
Calculate fuel needed and trip cost from distance, mpg or L/100km, and price per gallon.
Compare petrol and diesel and estimate annual driving fuel spend.
Annual fuel cost is one of the most overlooked factors when choosing or budgeting for a vehicle. Small differences in fuel efficiency compound into thousands of dollars over a car’s lifetime.
Annual fuel cost formula:
Annual Cost = (Annual Miles / MPG) × Price per Gallon
Or in metric:
Annual Cost = (Annual km / (100 / L/100km)) × Price per Liter
Simplified metric:
Annual Cost = Annual km × (L/100km / 100) × Fuel Price per Liter
Worked example (imperial):
Annual mileage: 15,000 miles. Fuel efficiency: 28 MPG. Fuel price: $3.50/gallon.
Annual Cost = (15,000 / 28) × $3.50 = 535.7 × $3.50 = $1,875/year
Worked example (metric):
Annual distance: 20,000 km. Efficiency: 8.5 L/100km. Price: $1.60/liter.
Annual Cost = 20,000 × (8.5 / 100) × $1.60 = 20,000 × 0.085 × 1.60 = $2,720/year
Cost comparison between two vehicles:
Annual Savings = (Miles/MPG_old × Price) − (Miles/MPG_new × Price)
Example: Switching from 22 MPG to 35 MPG at 15,000 miles/year, $3.50/gallon. Old: (15,000/22) × $3.50 = $2,386/year New: (15,000/35) × $3.50 = $1,500/year Annual savings: $886 — over 10 years, that is $8,860 in fuel alone.
Typical annual mileage benchmarks:
- US average: 13,500 miles (21,700 km)
- High commuter: 20,000–25,000 miles
- Low use / retiree: 5,000–8,000 miles
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.