Fuel Economy Calculator
Calculate actual MPG, km/L, or L/100km from odometer readings and fuel receipts.
Track fuel economy across multiple fill-ups to spot efficiency trends.
Fuel economy measures how efficiently a vehicle converts fuel into distance traveled. There are two common metrics: MPG (miles per gallon, used in the US) and L/100km (liters per 100 kilometers, used in most of the world). Annual fuel cost depends on both fuel economy and how many miles/km you drive per year.
MPG formula: MPG = Miles Driven ÷ Gallons Used
L/100km formula: L/100km = (Liters Used ÷ Kilometers Driven) × 100
Converting between the two: L/100km = 235.21 ÷ MPG
Annual fuel cost formula: Annual Cost = (Miles Driven per Year ÷ MPG) × Price per Gallon
Or in metric: Annual Cost = (km/Year ÷ 100) × L/100km × Price per Liter
Where:
- Miles Driven per Year — US average is approximately 13,500 miles
- MPG — combined city/highway fuel economy rating
- Price per Gallon — varies by region and fuel grade; US average $3.20–$4.50 for regular
Fuel economy benchmarks:
- Economy cars (Civic, Corolla): 32–40 MPG combined
- Midsize sedans: 28–35 MPG
- SUVs and crossovers: 22–30 MPG
- Full-size trucks: 16–22 MPG
- Hybrid vehicles: 45–60 MPG
- Electric vehicles: equivalent 90–130 MPGe
Worked example: Driver travels 12,000 miles/year in an SUV rated at 24 MPG. Gas price: $3.80/gallon.
Annual fuel cost = (12,000 ÷ 24) × $3.80 = 500 gallons × $3.80 = $1,900/year
If they switch to a hybrid at 50 MPG: Annual fuel cost = (12,000 ÷ 50) × $3.80 = 240 gallons × $3.80 = $912/year Annual savings = $988 — the hybrid pays back its premium in approximately 5–7 years.
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.