Petrol Cost per Km: Plan Any Trip's Fuel Bill
· 4 min read
How to find your car's real fuel average, work out petrol cost per kilometre and estimate the fuel bill for trips like Lahore to Islamabad.
The formula
- Litres needed = distance ÷ fuel average (km per litre)
- Trip cost = litres × petrol price
- Cost per km = petrol price ÷ fuel average
Find your real fuel average
The company figure is measured in ideal conditions. To find yours: fill the tank to the top, reset the trip meter, drive normally until the tank is low, then fill to the top again. Divide the kilometres driven by the litres you just added.
Do this twice — once in city driving and once on the motorway — because the two can differ by 30% or more.
Example: Lahore to Islamabad and back
The motorway route is about 380 km each way, 760 km in total. A 1300 cc car averaging 14 km/l needs about 54 litres. At around Rs 393 per litre, the fuel bill is roughly Rs 21,300 — plus motorway tolls.
Split between four passengers, that's about Rs 5,300 each.
What lowers your average
- AC in city traffic (10–20% more fuel).
- Speeds above about 100 km/h — drag rises sharply.
- Under-inflated tyres and a heavy boot.
- Long idling in traffic or while waiting.