How to Work Out the Fuel Cost of a Road Trip (and Split It Fairly)

Before a long trip, it helps to know how much you will spend on petrol. It helps you plan your budget, and if you are sharing the car, it helps everyone agree on a fair price.

The good news: the sum is simple. You only need three numbers.

The simple formula

Fuel cost = (distance ÷ km per litre) × price of one litre

In words: first find out how many litres the trip needs, then multiply by the petrol price.

Let’s go through the three numbers one by one.

Step 1: Find the distance

Open the map app on your phone and type in where you start and where you finish. It will show the distance in kilometres.

Use the whole trip, from your pickup point to your last stop, not just the motorway. If you are coming back the same day, double it.

Step 2: Know your car’s km per litre

This number tells you how far your car goes on one litre of petrol. Every car is different, and the same car does better on an open motorway than in city traffic.

The best way to know your own number is to measure it:

1. Fill the tank to full and write down the reading on the odometer (the distance meter).
2. Drive normally until the tank is about half empty.
3. Fill it to full again and note how many litres you put in.
4. Divide the kilometres you drove by those litres.

For example, if you drove 360 km and then needed 30 litres to fill up again, your car does 360 ÷ 30 = 12 km per litre.

Step 3: Check today’s petrol price

Petrol prices in Pakistan change often. In this article we use PKR 393.64 a litre, the price from 6 October 2026. Before your trip, check the latest price from OGRA or the board at your petrol pump.

A worked example: Islamabad to Peshawar

From central Islamabad to central Peshawar is about 185 km. Say your car does 12 km per litre.

1. Litres needed: 185 ÷ 12 = 15.4 litres
2. Cost: 15.4 litres × PKR 393.64 = PKR 6,069

A return trip, 370 km, costs about PKR 12,137 in petrol.

How the numbers change with your car

The same trip costs more in a car that uses more fuel. Here is what two common trips cost in petrol, for cars that do 10, 12 or 15 km per litre:

For more about these two routes, see our guides to Islamabad to Peshawar and Lahore to Islamabad.

Don’t forget the other costs

Petrol is the biggest cost, but not the only one. A few things change the real total:

• Tolls. Motorways charge a toll. The rates change from time to time, so check before you go.
• AC, traffic and speed. The AC, stop-start city traffic and driving fast all use more fuel than the simple sum says.
• Heavy luggage. A full boot and a full car use a little more fuel.
• Wear on the car. Tyres, oil and servicing cost money too. This is why a driver may ask for a little more than the petrol cost alone.

A good habit is to add about 10% to the petrol figure, to be safe.

How to split the cost fairly when you carpool

When several people share a car, the simplest fair method is to split the petrol equally between everyone in the car, including the driver.

For the Islamabad to Peshawar example (PKR 6,069 in petrol):

A few simple rules keep it fair and friendly:

• Agree before the trip, not at the end. Write the price per seat in your WhatsApp chat.
• Decide about tolls. Either add the toll to the shared cost or include it in the price per seat. Just say which.
• Keep it fair, not a business. Carpooling is about sharing a trip you are already making, not earning from it.
• Pay in person. Passengers pay the driver directly, for the seat they actually used.

On YauzaiSafar, the driver sets a price per seat when posting a ride, so every passenger sees the price before booking. Using the sum above, a driver can set a fair price in a minute.

Quick checklist

• Distance from your phone’s map app
• Your car’s km per litre (measured, if you can)
• Today’s petrol price
• Litres = distance ÷ km per litre
• Cost = litres × price
• Add tolls, and about 10% extra to be safe
• Split equally, driver included, and agree before the trip

Sharing fuel is the main reason carpooling saves money. To see how sharing a car also means less pollution, read how carpooling cuts carbon emissions. If you drive to work every day, the savings add up fast: see carpooling to work.