Fuel Cost Calculator (Free — Trip, Commute & Car Comparison)
Use this free fuel cost calculator to find out how much a journey will cost in fuel, calculate your monthly commuting costs, or compare the running costs of two different vehicles. Works with kilometres and miles, litres and gallons. Once you have your results, use our free AI Cost Analysis below to get a personalised breakdown with money saving recommendations.
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🤖 AI Cost Analysis
Enter your fuel cost results below — include your journey details, vehicle type or monthly mileage — and get a personalised cost analysis with money saving tips instantly.
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How to Use the Fuel Cost Calculator
Choose your mode — Trip Cost, Monthly Cost, or Compare Two Cars. Enter your distance, fuel efficiency and fuel price, then click Calculate. All units are supported including L/100km, MPG (UK and US) and km/L.
How Fuel Cost Is Calculated
Fuel cost is calculated by dividing your distance by your fuel efficiency to get litres used, then multiplying by the fuel price per litre.
Formula: Fuel Cost = (Distance ÷ 100) × L/100km × Price per litre
Save Money on Fuel
Even small improvements to your driving habits can significantly reduce how much you spend on fuel each month. Here are the most effective ways to cut your fuel costs:
Drive smoothly and avoid harsh acceleration and braking. Aggressive driving can increase fuel consumption by up to 30%.
Keep your tyres properly inflated. Under-inflated tyres increase rolling resistance and can reduce fuel efficiency by up to 3%.
Remove unnecessary weight from your car. Every extra 50kg reduces fuel efficiency by around 1-2%.
Use air conditioning sparingly at lower speeds. At motorway speeds, windows down creates more drag than AC uses.
Plan your routes to avoid traffic. Stop-start driving in congestion uses significantly more fuel than steady motorway driving.
Regular servicing keeps your engine running efficiently. A well-maintained engine can use up to 10% less fuel.
FAQs
What is L/100km?
Litres per 100 kilometres is the metric measure of fuel efficiency used in most countries. It tells you how many litres of fuel your car uses to travel 100km. A lower number means a more fuel-efficient car.
What is MPG?
Miles per gallon is the imperial measure of fuel efficiency used in the UK and US. A higher MPG means a more fuel-efficient car.
Does this work for diesel cars?
Yes — just enter your diesel price and your car’s fuel efficiency. The calculator works the same for petrol and diesel.
Can I use this for any country?
Yes — just enter your local fuel price and choose your preferred units. The calculator works worldwide.
How much does fuel cost per km?
Divide your fuel price per litre by your car’s fuel efficiency. For example at $1.80/L with a car using 8L/100km your cost is $1.80 × 8 ÷ 100 = $0.144 per km.
How can I reduce my fuel costs?
Maintain steady speeds, keep tyre pressure correct, reduce air conditioning use and remove unnecessary weight from your car. Even small changes can improve fuel efficiency by 5-10%.
Does this work for electric vehicles?
This calculator is designed for petrol and diesel vehicles. For EVs the equivalent calculation uses kWh per 100km multiplied by your electricity rate per kWh.
Can I get a personalised analysis of my fuel costs?
Yes — scroll down to the AI Cost Analysis below the calculator. Enter your results including your journey details and vehicle type to get a personalised breakdown with practical money saving tips instantly.
Is this calculator free?
Yes, completely free with no sign-up needed.