Free calculator
How far can I drive on a budget?
Enter the money you want to spend, the price per litre and your mpg, and see how many litres you get and how far they take you.
Prices prefilled from the official Fuel Finder data, updated 28 August 2026. Change any box and the answer updates as you type.
Turning money into miles
When you are putting in a set amount rather than filling the tank, the useful question is how far it will get you. Your money divided by the price per litre gives the litres, and litres times your mpg, allowing for the gallon conversion, gives the miles. The price box is prefilled with today's typical UK petrol price, so change it to the price at your pump, or to the diesel price for a diesel car.
The answer moves a long way with mpg. Twenty pounds in a small efficient car can be well over a hundred miles, while the same twenty pounds in a big thirsty one might be sixty. If you are not sure of your real mpg, our mpg calculator works it out from one tank.
Getting more miles for the same money
At a fixed budget the only way to go further is to pay less per litre or use less fuel. The first is the easier win. A few pence a litre difference between forecourts is a few extra miles on every twenty pounds, so use the price finder to put your money in at the cheapest station near you.
Common questions
How far can I drive on 20 pounds of petrol?
At today's typical price twenty pounds buys around 12 litres, which in a 45 mpg car is roughly 120 miles. A small efficient car goes further and a large thirsty one much less, so enter your own mpg above for a realistic figure.
How many litres do I get for 20 pounds?
Divide 2000 by the price in pence per litre. At 162p a litre that is about 12.3 litres. The cheaper the forecourt, the more litres you get for the same money.
Is it better to fill up or put in a set amount?
Filling up does not change the price per litre, so neither saves money by itself. What matters is where you buy. A full tank does let you choose when and where to fill next rather than being forced to buy at an expensive station when you run low.