Fuel Consumption Calculator

How to Use the Fuel Consumption Calculator

The Fuel Consumption Calculator computes your vehicle fuel economy, converts between MPG and L/100km, estimates fuel costs for trips, and helps you compare the running costs of different vehicles. It is your essential tool for understanding and optimizing fuel expenses.

Calculate Fuel Economy

Enter the distance traveled and the amount of fuel used. The calculator computes your fuel economy in multiple units: miles per gallon (MPG), liters per 100 kilometers (L/100km), and kilometers per liter (km/L). A car that travels 350 miles on 10 gallons gets 35 MPG, equivalent to about 6.72 L/100km.

Unit Conversions

MPG to L/100km: L/100km = 235.215 / MPG. 30 MPG = 7.84 L/100km. L/100km to MPG: MPG = 235.215 / L/100km. 8 L/100km = 29.4 MPG. Note that MPG and L/100km have an inverse relationship; higher MPG means lower L/100km (better efficiency).

Trip Fuel Cost Estimator

Enter the trip distance, your vehicle fuel economy, and the current fuel price. The calculator estimates total fuel needed and cost. A 500-mile trip at 25 MPG with gas at $3.50/gallon: 500/25 = 20 gallons × $3.50 = $70 in fuel. This helps budget for road trips and commuting costs.

Vehicle Comparison

Compare annual fuel costs between vehicles. A car getting 25 MPG driving 12,000 miles/year at $3.50/gallon costs $1,680 in fuel. Upgrading to 35 MPG reduces the annual cost to $1,200, saving $480 per year. Over 5 years, the more efficient vehicle saves $2,400 in fuel alone.

Improving Fuel Economy

Maintain proper tire pressure (saves 1-3%). Remove excess weight. Avoid aggressive acceleration and braking. Use cruise control on highways. Reduce idle time. Keep up with maintenance (air filters, spark plugs, oil changes). Highway driving is typically 20-30% more fuel-efficient than city driving.

Frequently Asked Questions

Q: Why does Europe use L/100km while the US uses MPG?

A: L/100km tells you how much fuel a distance requires (consumption rate). MPG tells you how far you can go on a unit of fuel (efficiency rate). They are inverse measures of the same thing. L/100km makes cost comparisons easier; MPG makes range estimation easier. Neither is inherently superior.

Q: What is considered good fuel economy?

A: For conventional gasoline cars: over 30 MPG (under 8 L/100km) is good, over 40 MPG (under 6 L/100km) is excellent. Hybrid vehicles typically achieve 40-60 MPG. Electric vehicles express efficiency in kWh per 100 miles (typically 25-35 kWh/100mi), which converts to roughly 100+ MPGe.

Q: How does driving speed affect fuel consumption?

A: Most vehicles achieve peak fuel efficiency at 45-65 mph. Above 65 mph, aerodynamic drag increases significantly (proportional to speed squared). Driving at 75 mph typically uses 15-25% more fuel than driving at 55 mph. Each 5 mph above 50 is roughly equivalent to paying an extra $0.20-0.30 per gallon.