Fuel Cost Calculator London

Fuel Cost Calculator for London

The UK average pump price for unleaded petrol was 172.78p a litre in the week starting 2 November 2026, and diesel was 198.58p a litre, according to the Department for Energy Security and Net Zero (DESNZ). London prices are usually close to the national average, with supermarket forecourts cheaper than motorway services.

Facts that change the answer

• UK unleaded petrol: 172.78p/litre (DESNZ, week of 2 Nov 2026)
• UK diesel: 198.58p/litre
• Diesel premium over petrol: about 25.8p a litre
• Units preset here: km and litres (UK mpg is imperial, not US)

Worked example for London

London to Manchester and back is about 640 km (400 miles). A petrol car using 6.5 litres per 100 km needs about 41.6 litres, which costs about £71.88 at 172.78p. The same trip in a diesel car using the same amount of fuel would cost about £82.61 at 198.58p.

UK drivers usually think in miles per gallon, but UK gallons are imperial (4.546 litres), not US gallons (3.785 litres). To avoid mixing them up, use the km and litres setting and choose L/100 km or km per litre, or divide your UK mpg by 2.825 to get km per litre.

Driving inside London has costs the fuel figure does not show. Most of central London is in the Congestion Charge zone during charging hours, and the whole of Greater London is in the Ultra Low Emission Zone, which charges older petrol and diesel cars that do not meet the standards. Check both on the Transport for London website before you drive in.

DESNZ publishes the weekly average every Tuesday. Prices at individual stations can be found through the government's Fuel Finder data, which many comparison apps use.

Sources: GOV.UK: Weekly road fuel prices (DESNZ). Checked 5 November 2026. For how the maths works, see the Fuel Cost Calculator guide.