Fuel Consumption Calculator
Two tools in one: calculate your vehicle's fuel efficiency from a known journey, then estimate the fuel cost for any upcoming trip. Toggle between metric (L/100km) and imperial (MPG) units instantly.
Section 1 — Calculate Fuel Efficiency
Enter the distance driven and the fuel you used to get all efficiency metrics at once.
Section 2 — Trip Cost Estimator
Enter a trip distance, your vehicle's fuel efficiency, and the current fuel price to estimate the total fuel cost.
Fuel Efficiency Formulas
L/100km = (fuel_L / dist_km) × 100
Litres consumed per 100 km driven. Lower = more efficient.
km/L = dist_km / fuel_L
Distance travelled on one litre of fuel. Higher = more efficient.
MPG (US) = km/L × 2.35215
US miles per gallon (1 US gal = 3.785 L, 1 mi = 1.609 km).
MPG (UK) = km/L × 2.82481
Imperial miles per gallon (1 UK gal = 4.546 L).
Fuel needed = dist × efficiency / 100
For metric: L = km × (L/100km) / 100.
Example Calculation
Frequently Asked Questions
MPG stands for Miles Per Gallon — a measure of fuel efficiency used primarily in the US and UK. A higher MPG means the vehicle travels more miles on one gallon of fuel, making it more economical. US MPG and UK (Imperial) MPG differ because they use different gallon sizes: 3.785 L (US) vs 4.546 L (UK).
To convert L/100km to US MPG: MPG = 235.215 / (L/100km). For example, 8 L/100km = 235.215 / 8 ≈ 29.4 MPG (US). For UK MPG: MPG = 282.481 / (L/100km). Lower L/100km always means better fuel economy.
Drive smoothly by accelerating and braking gradually. Maintain correct tyre pressure (under-inflation increases rolling resistance by 0.5% per 10 kPa). Use cruise control on motorways. Reduce air conditioning use. Remove roof racks when not in use. Keep up with engine servicing — dirty air filters and old spark plugs reduce efficiency significantly.
The UK uses the Imperial gallon (4.546 litres) while the US uses the smaller US gallon (3.785 litres). The same vehicle will therefore show a higher MPG figure in UK terms than in US terms for the same journey. When comparing fuel economy between vehicles, always confirm which MPG standard is being quoted.
A modern petrol/gasoline car averages 6–9 L/100km (26–39 MPG US). Hybrids typically achieve 3–6 L/100km (39–78 MPG US). Diesel cars often achieve 4–7 L/100km. SUVs and trucks typically consume 9–15 L/100km. Electric vehicles are typically rated in kWh/100km rather than L/100km.
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