Fuel Cost Calculator

How to Use the Fuel Cost Calculator

This fuel cost calculator works out how much petrol or diesel a trip will cost in Australia. Enter the distance, choose one way or return, add your car's fuel consumption and the price per litre, and you'll see the trip cost, the litres needed, the cost per kilometre and each person's share. Add how often you make the trip and it becomes a yearly fuel cost estimator — handy for budgeting a daily commute.

How to Calculate Fuel Cost

Worked Example: Sydney to Canberra and Back

Sydney to Canberra is about 290 km by road one way, so a return trip is 580 km. In a car using 8.5 L/100km with petrol at $2.05 a litre, you'd use about 49.3 litres, for a total fuel cost of $101.06 — about 17.4c per km ($17.42 per 100 km). Split between two people, that's $50.53 each.

Fuel price matters: if petrol were 20c a litre cheaper the trip would cost $91.20, and 20c dearer it would cost $110.93. Vehicle choice matters even more — the same trip would cost roughly $59.45 in a hybrid using 5 L/100km and $166.46 in a large 4WD using 14 L/100km.

City vs Highway Fuel Consumption

Most cars use noticeably more fuel in stop-start city traffic than on the open road, because accelerating from a standstill takes far more energy than cruising. Australian fuel consumption labels show an urban and an extra-urban figure alongside the combined one: use the urban figure for a city commute, the extra-urban figure for a country highway trip, and the combined figure for a mix. Very high highway speeds push consumption back up, so a trip at 110 km/h will use more than the same trip at 90 km/h.

How to Split Fuel Costs Fairly

For a shared road trip, the simplest fair split is the total fuel cost divided evenly by everyone in the car — enter the number of people above. If passengers join for only part of the journey, work out each leg separately and split each leg among the people on it. Some groups also have passengers chip in a little extra towards tolls, parking or wear on the driver's car, which this petrol calculator doesn't include.

Tips to Cut Your Fuel Costs

• Keep tyres inflated to the pressure on the tyre placard — under-inflated tyres increase fuel use.
• Drive smoothly and ease off the speed; hard acceleration and high speeds burn more fuel.
• Remove unnecessary weight and take roof racks or pods off when you're not using them.
• Compare prices before you fill up using fuel price apps or your state's fuel price-monitoring service, and try to buy near the low point of the price cycle.
• Combine errands into one trip and keep your car serviced on schedule.

Frequently Asked Questions

How do I calculate fuel cost for a trip?

Multiply the distance by your car's fuel consumption in L/100km and divide by 100 to get the litres you'll use, then multiply the litres by the price per litre. For example, 100 km at 8 L/100km uses 8 litres, which costs $16.00 at $2.00 a litre. The calculator above does this instantly and doubles the distance for you if you pick Return.

Is this petrol cost calculator set up for Australia?

Yes. It uses kilometres, litres and L/100km — the units on Australian fuel consumption labels — and shows costs in Australian dollars, with the price entered either in dollars or cents per litre as you'd see on a servo price board. It works the same for petrol, diesel or LPG, as long as you enter the right consumption figure and price for that fuel.

Can I use this as a petrol trip calculator to split costs with passengers?

Yes — enter how many people are sharing the trip and the calculator divides the fuel cost evenly between them. An even split is the simplest fair approach for a shared road trip; if someone is only along for part of the way, you could split each leg separately instead. Remember tolls and parking aren't included, so agree on those separately.

What is a gas price calculator — is it the same as a fuel calculator?

"Gas" is the American word for petrol, so a gas price calculator is the same idea as this fuel calculator. US tools usually work in miles per gallon and dollars per gallon, while Australia uses litres and L/100km. If you only have a US or UK mpg figure for your car, choose mpg (US) or mpg (UK) in the economy dropdown and the calculator converts it to L/100km for you.

Where do I find my car's fuel consumption in L/100km?

New cars sold in Australia carry a fuel consumption label on the windscreen showing combined, urban and extra-urban figures in L/100km, and the same numbers are usually in the owner's manual. You can also look up most models on the Australian Government's Green Vehicle Guide (greenvehicleguide.gov.au). Many cars also show average consumption on the dashboard trip computer, which is often closer to your real-world use than the label.

Why does my car use more fuel than the label says?

Label figures come from standardised laboratory tests, so real-world consumption is often higher. Stop-start city traffic, short trips with a cold engine, heavy loads, roof racks, towing, hills, air-conditioning and higher speeds all add to fuel use. For a more realistic estimate, use the urban figure for city driving, the extra-urban figure for country highways, or your trip computer's average.

Is diesel or petrol cheaper to run?

It depends on both the price per litre and how many litres the vehicle uses. Diesel engines usually use fewer litres per 100 km than a comparable petrol engine, but diesel can be priced higher or lower than unleaded at different times. Enter each vehicle's L/100km and the matching fuel price to compare the trip cost directly.

What price should I enter in the fuel calculator?

Enter the price you'll actually pay at your local station, since prices vary by fuel type, location and day. Petrol prices in several capital cities move in regular cycles, rising sharply and then drifting down over a period of days or weeks, so filling up near the bottom of the cycle can save money. State fuel price-monitoring services and fuel price apps can show current prices near you.

How can I calculate my yearly fuel cost?

Enter how many times a week you make the trip — for example 5 for a weekday return commute — and the calculator shows the weekly, monthly and yearly fuel cost. It assumes 52 weeks a year, so reduce the trips per week if you take holidays or work from home some days.