How Much Does It Cost to Fill a Tank in the UK?

How much a full tank costs depends on three things: the price per litre, the size of your tank, and how empty you are when you fill it. Here are the numbers at the national averages for the week commencing 26 October 2026: petrol 174.07p and diesel 199.22p a litre.

Cost of a full tank from empty

Smaller cars usually have tanks of around 35 to 45 litres, family cars around 50 to 60, and large SUVs and vans 70 litres or more. Your handbook gives the exact figure. Most people fill from partly full, so the actual cost is lower.

The quick sum

Litres × price in pence ÷ 100 = cost in pounds.

For example, 40 litres at 174.07p is 40 × 174.07 ÷ 100 = £69.63.

What each extra penny costs

Every 1p a litre adds about 55p to a 55-litre fill. So:

Our database shows a gap of more than 50p a litre between the cheapest and dearest E10 stations. On a 55-litre tank that is about £27. See how to find the cheapest petrol near you.

Litres, gallons and the pump

UK pumps sell fuel in litres, but mpg figures use gallons. One UK gallon is 4.546 litres. At 174.07p a litre, a gallon of petrol costs about £7.91.

How far does a tank take you?

Multiply tank litres by mpg and divide by 4.546. A 50-litre tank at 40 mpg gives about 440 miles. Real-world range is usually lower, especially in winter or with heavy loads. See winter driving and fuel economy.

Is it better to fill up fully or top up?

A full tank adds some weight, but the effect on fuel economy is small. The bigger factor is price: if you are near a cheap station, fill up. If you are not, put in only what you need to reach one. Never run the tank close to empty just to chase a saving, since it can damage some fuel systems and leaves you stuck with whatever the nearest station charges.

Compare prices near you before you fill.

Figures use national average prices from weekly reports and will change as prices move.

Compare prices in your city: London, Birmingham, Manchester, Leeds, Glasgow, or see petrol prices by city.