Fuel Cost Calculator

What this calculator does

The Fuel Cost Calculator turns a distance and a mileage figure into money. Give it how far you are going, how much fuel your vehicle uses and what fuel costs where you are, and it returns the fuel for the trip, the total cost, the cost of each kilometre and the cost of each 100 km.

Around that core it adds the arithmetic people usually do badly in their heads: round trips, full-tank cost and full-tank range, daily commute scaled to monthly and annual spend, a road-trip cost split between passengers, and a side-by-side comparison of two vehicles' efficiency.

It also converts between the four mileage standards that make comparisons confusing — kilometres per litre, litres per 100 km, US MPG and UK MPG — and handles petrol, diesel, CNG, LPG and EV, so an electric vehicle priced per kWh works the same way as a petrol car priced per litre.

How to use it

1. Enter the distanceType the one-way distance and pick kilometres or miles. If the journey is there and back, switch on the round trip option rather than doubling the number yourself — the tool then doubles the distance for every figure it derives, including the commute projections.
2. Enter your vehicle's mileage in whatever unit you have itThe unit selector accepts km/L, L/100 km, US MPG and UK MPG. Everything is converted to km/L internally, so it does not matter which one your manual quotes — just make sure the selector matches the number you typed, because 40 MPG and 40 km/L are wildly different vehicles.
3. Set the fuel type and priceChoose petrol, diesel, CNG, LPG or EV, then enter today's price per litre — or per kg, or per kWh for an EV. The price is yours to supply: the calculator does not fetch live fuel prices, which its own FAQ states plainly.
4. Read the trip resultYou get fuel needed, total fuel cost, cost per kilometre and cost per 100 km. Cost per 100 km is the number worth remembering, because it compares vehicles and fuel types directly regardless of how far you happen to be driving.
5. Add tank capacity for rangeEntering the tank size gives full-tank cost and full-tank range — tank capacity multiplied by mileage. That range is the arithmetic maximum on the mileage you entered, not a promise; treat the last tenth of a tank as unusable.
6. Use the commute and comparison sectionsThe commute calculator scales a daily distance into monthly and annual spend. The mileage comparison shows what a second vehicle's efficiency would cost over the same distance. The trip scenarios load realistic distances so you can see the shape of the result before entering your own.

What the results mean

Fuel needed

The volume the trip consumes: total distance divided by mileage in km/L. For a round trip this already counts both legs. In EV mode the same division gives kWh rather than litres.

Total fuel cost

Fuel needed multiplied by the price you entered. It is fuel only — tolls, parking, tyres, servicing and depreciation are not in this number unless you add them where the tool allows extra costs.

Cost per kilometre

Total fuel cost divided by total distance. This is the figure to quote when someone asks what your car costs to run, and the one to use when deciding whether a detour is worth it.

Cost per 100 km

Cost per kilometre multiplied by 100. It is the fair way to compare a petrol car against a diesel or an EV, because it removes both the distance and the unit of fuel from the comparison.

Full-tank cost and range

Tank capacity times price, and tank capacity times mileage. The range assumes the mileage you entered holds for the whole tank, which real driving rarely delivers — read it as the best case.

Commute projection and per-passenger split

The daily figure scaled by your working days into monthly and annual totals, and the trip cost divided by the number of people sharing it. Both are straightforward multiplication and division of the trip result, so they inherit its accuracy exactly.

The formula

These are the expressions the calculator evaluates, written out so you can reproduce any result by hand.

Worked example

Limits worth knowing

A browser can only report what the platform gives it. These are the honest boundaries of this page, so a result is never read as more than it is.

• It does not use live fuel prices. Every price is the one you type; the page's “Does the calculator use live fuel prices?” FAQ says so directly, and prices move daily and by state, city and pump.
• It does not know your real-world mileage. The number you enter is the number it uses — manufacturer claims are optimistic, and the page has its own FAQ on this. For a figure you can trust, work out your own mileage from a full-to-full tank over a few hundred kilometres.
• Actual cost varies for reasons no calculator can model: traffic and idling, air conditioning, terrain and gradients, load and passengers, tyre pressure, roof boxes, and how hard you accelerate. The page lists these under why actual fuel cost can differ.
• Fuel cost is not running cost. Tolls, parking, tyres, servicing, insurance and depreciation are separate; add them explicitly where the tool provides fields rather than assuming the trip total covers them.
• The full-tank range is arithmetic, not a driving guarantee. It assumes the entered mileage across the whole tank and no reserve, and real conditions will come in under it.
• For an EV, the same division holds but the mileage is km per kWh and the price is per kWh. Charging losses and battery conditioning mean the wall-meter figure will exceed the calculated energy.

Tips

• Measure your own mileage once, then reuse it. Fill the tank, note the odometer, drive normally for a few hundred kilometres, fill up again: litres added divided into distance covered is your true km/L, and it is usually 10–20% below the brochure.
• Compare vehicles on cost per 100 km, never on mileage in different units. The comparison section exists for this — a 15 km/L petrol car and a 20 km/L diesel can land closer than the mileage gap suggests once the fuel price differs.
• Run the commute projection before arguing about a longer route. A two-kilometre daily detour looks trivial and costs a visible amount over a year, which the annual figure makes obvious.

Troubleshooting

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