Fuel Cost Calculator
Plan what a drive will really cost: one trip with tolls and a passenger split, a daily commute over a month and a year, or several vehicles side by side. Every unit is chosen explicitly: km or miles, km/L, L/100 km or US/UK mpg, per litre or per gallon.
Runs in your browser. Your data is not uploaded.How our tools work
For your notes; it doesn’t change the maths.
From your dashboard, a fill-up log or the manual.
What you pay at the pump. No prices are built in.
Tolls, parking and other costs (optional)
Costs for the whole trip, such as tolls, parking, a ferry or road fees. They’re added to the fuel.
Split the cost (optional)
Including the driver.
Fuel economy converter
Convert between km/L, L/100 km and US or UK miles per gallon. A UK gallon is about 20% bigger than a US one.
How do I calculate the fuel cost of a trip?
Divide the distance by your vehicle’s fuel efficiency to get the fuel needed, then multiply by the fuel price. A 300 km trip at 15 km/L needs 300 ÷ 15 = 20 litres, which at PKR 280 a litre costs PKR 5,600. Add tolls or parking for the total, and double the distance for a round trip.
- Choose Trip cost, Monthly commute or Vehicle comparison at the top.
- Enter the distance in km or miles and pick one way, round trip or several trips.
- Enter your fuel efficiency in km/L, L/100 km, US mpg or UK mpg, or pick a vehicle type for a rough estimate you can edit.
- Enter the fuel price per litre, US gallon or UK gallon. Add tolls, parking or a passenger split if you need them, and read the results as you type.
Formulas & Methods
Fuel from km/L
Example: 300 ÷ 15 = 20 litres
Fuel from L/100 km
Example: 250 × 8 ÷ 100 = 20 litres
Fuel from miles per gallon
Example: 300 ÷ 25 = 12 US gallons
Fuel cost
Example: 20 × 280 = 5,600
Total trip cost
Example: 5,600 + 800 = 6,400
Cost per person
Example: 6,400 ÷ 4 = 1,600
Monthly commute fuel
Example: 4 L × 260.71 ÷ 12 = 86.9 litres
Key features
Trip, commute and comparison modes
Cost one journey, a regular commute from a day to a year, or up to six vehicles over the same trip.
Every unit chosen, nothing assumed
Kilometres or miles; km/L, L/100 km, US or UK mpg; a price per litre, US gallon or UK gallon. Mixed units are converted exactly.
Tolls, parking and a fair split
Add named trip costs, see fuel and other costs side by side, and split the total with or without the driver paying.
Cheapest and most efficient vehicle
The comparison names the cheapest and the most fuel-efficient vehicle, the saving per trip and in percent, and a monthly and yearly estimate.
Fuel price changes
Enter a new pump price to see the difference per trip, or per month and year for a commute.
Built-in economy converter
Convert between km/L, L/100 km, US mpg and UK mpg with the same exact constants the calculator uses.
Common uses
- Compare a petrol car with a diesel or hybrid before buying
- See what a fuel price rise does to your monthly spending
Supported formats and limits
- Distance
- Kilometres or miles (1 mile = 1.609344 km)
- Fuel efficiency
- km/L, L/100 km, miles per US gallon, miles per UK gallon
- Fuel price
- Per litre, per US gallon (3.785411784 L) or per UK gallon (4.54609 L)
- Currency
- PKR, USD, EUR, GBP, INR, AED, SAR, CAD, AUD or none: a label only, nothing is converted
- Limits
- Up to 1,000,000 km or miles a trip, 10 extra costs, 6 vehicles, 100 people
Worked example: a 300 km trip
A car that does 15 km/L drives 300 km, fuel costs PKR 280 a litre, and the motorway tolls are PKR 800. Each step below is what the calculator does.
- Fuel needed: 300 ÷ 15 = 20 litres.
- Fuel cost: 20 × 280 = PKR 5,600.
- Total trip cost: 5,600 + 800 = PKR 6,400, about PKR 21.33 per km.
- Shared by four people, driver included: 6,400 ÷ 4 = PKR 1,600 each.
- A round trip doubles the fuel to 40 litres (PKR 11,200), and the tolls if you pay them both ways.
What is fuel efficiency, and which unit should I use?
Fuel efficiency says how far a vehicle goes on a quantity of fuel, or how much fuel it needs for a distance. km/L and mpg are distance per fuel, so a higher number is better. L/100 km is fuel per distance, so a lower number is better. Use the unit your dashboard, manual or fill-up log gives you; the calculator converts it exactly.
The two kinds are reciprocals, which is why improvements look different. Going from 10 to 12 km/L cuts fuel use by about 17%, while going from 10 to 8 L/100 km cuts it by 20%. To convert, divide 100 by either figure: 15 km/L is 6.67 L/100 km, and 8 L/100 km is 12.5 km/L.
Why is US mpg different from UK mpg?
A US gallon is 3.785 litres and a UK (imperial) gallon is 4.546 litres, about 20% more. So the same car shows a higher mpg in the UK: 30 US mpg is about 36 UK mpg. Pick the gallon that matches where your figure comes from, and price per US or UK gallon to match the pump. To get L/100 km, divide 235.21 by US mpg or 282.48 by UK mpg.
How is a monthly commute worked out?
The commute mode multiplies your one-way distance by the trips a day (2 for there and back) to get a travel day. It then counts travel days in a year: days a week × 365 ÷ 7, or days a month × 12. A month is a twelfth of that year and a week is the year ÷ 52.14, so the months add up exactly to the year. Five days a week gives 260.71 travel days a year, or about 21.7 a month.
Daily tolls, parking and other costs are scaled the same way and shown separately from fuel, so you can see which one drives the total. Public holidays and leave aren’t taken off; enter fewer days to allow for them.
How do I split the cost between passengers?
Divide the total trip cost, fuel plus tolls and parking, by the number of people paying. Some groups let the driver travel free in return for driving, so the calculator lets you choose whether the driver pays a share. Four people with the driver paying split PKR 6,400 into PKR 1,600 each; with the driver free, three people pay about PKR 2,133.33.
Why real fuel use differs from the estimate
The result is only as accurate as the efficiency you enter. Official figures come from standard lab tests and are usually better than real driving. Short trips, a cold engine, stop-and-go traffic, high motorway speeds, air conditioning, roof boxes, heavy loads, low tyre pressure and hills all use more fuel. A well-maintained car driven smoothly uses less.
The most reliable figure is your own. Fill the tank, reset the trip meter, and at the next fill divide the distance by the litres added for km/L, or the litres by the distance × 100 for L/100 km. The vehicle-type presets are rough averages, not manufacturer figures, and are there only when you have nothing better.
Frequently Asked Questions
Can I compare two vehicles?
Yes. The Vehicle comparison mode takes up to six vehicles over the same trip, each with its own efficiency, fuel type and optional fuel price. It names the cheapest and the most fuel-efficient and shows the saving per trip, a month and a year.
Does the calculator use live fuel prices?
No. Prices change by country, city, station and week, so you enter the price you pay. The currency is a label only; nothing is converted or looked up.
Does VektraTool store my trips or vehicles?
No. Distances, prices and vehicles stay in the page and are gone when you close it. Analytics, if you allow them, record only that a mode was used, never a number you typed.
Does it work for electric cars?
No, it is for liquid fuel and gas. For an electric car, multiply the distance by the energy use per km or mile in kWh and by your price per kWh; the Electricity Cost Calculator handles the kWh part.
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