Live data, checked today at 16:13 (UK time). 8,155 forecourts: 8,071 from Fuel Finder, the government service every UK forecourt must report its prices to, and 84 from open retailer feeds. Wrong price? Report it to Fuel Finder.
Fuel cost calculator: what will your journey cost?
At today's UK average of 174.6p a litre, a petrol car doing 45 mpg costs 17.6p a mile, so 100 miles is about £17.64. Enter your own distance and mpg: the price is filled in from our live forecourt data, checked 29 September 2026 at 16:13 UK time.
£16.93Fuel cost, 100 miles
16.9p a mile in a petrol car doing 45 mpg (6.3 litres per 100 km).
Based on 167.6p a litre, the average unleaded price across 512 stations in Northern Ireland, checked 29 September 2026 at 16:13 UK time.
- Cost per mile16.9p10.5p a km
- Cost per person£16.93Just you. Add people above to split it
- Fuel used10.1 litres2.2 UK gallons for 100 miles
- Price a litre167.6pNorthern Ireland average
Pay less for this trip
At the cheapest unleaded in Northern Ireland, 149.9p a litre at Corner filling station, 66B Drumconvis Rd, Coagh, Cookstown, this trip would cost £15.14 instead of £16.93 at the average price: £1.79 less.
See every petrol price in Northern Ireland, or search near your postcode:
The same trip in an electric car
| How it is charged | This trip | Against petrol |
|---|---|---|
| Home, EV off-peak tariff | £2.16 | Saves £14.77 |
| Home, standard rate | £7.11 | Saves £9.82 |
| Public rapid charger | £20.81 | Costs £3.88 more |
Compare with your own electric car, mileage and local prices.
Thinking of charging at home? Search home EV chargers on Amazon UKAs an Amazon Associate, fuelprices.org.uk earns from qualifying purchases. This is an affiliate link, at no extra cost to you. Affiliate disclosure.What a mile costs at today's prices
These tables use the live UK averages: unleaded 174.6p, diesel 199.7p a litre. Find your car's mpg in the first column.
| Fuel economy | Litres per 100 km | Petrol, per mile | Petrol, 100 miles | Diesel, per mile | Diesel, 100 miles |
|---|---|---|---|---|---|
| 30 mpg | 9.4 | 26.5p | £26.46 | 30.3p | £30.26 |
| 35 mpg | 8.1 | 22.7p | £22.68 | 25.9p | £25.94 |
| 40 mpg | 7.1 | 19.8p | £19.84 | 22.7p | £22.70 |
| 45 mpg | 6.3 | 17.6p | £17.64 | 20.2p | £20.17 |
| 50 mpg | 5.6 | 15.9p | £15.87 | 18.2p | £18.16 |
| 55 mpg | 5.1 | 14.4p | £14.43 | 16.5p | £16.51 |
| 60 mpg | 4.7 | 13.2p | £13.23 | 15.1p | £15.13 |
| 65 mpg | 4.3 | 12.2p | £12.21 | 14.0p | £13.97 |
| Trip | Petrol | Diesel |
|---|---|---|
| 10 miles | £1.76 | £1.65 |
| 25 miles | £4.41 | £4.13 |
| 50 miles | £8.82 | £8.25 |
| 100 miles | £17.64 | £16.51 |
| 200 miles | £35.28 | £33.01 |
| 300 miles | £52.92 | £49.52 |
| 500 miles | £88.19 | £82.53 |
Questions
How do I work out the fuel cost of a journey?
Divide the distance by your car's miles per gallon to get the gallons used, multiply by 4.54609 litres per UK gallon, then multiply by the price per litre. At 174.6p a litre and 45 mpg, 100 miles uses 10.1 litres and costs £17.64. The calculator above does this for you, with today's price filled in.
How much does a mile of petrol cost?
At today's UK average of 174.6p a litre, a petrol car doing 45 mpg pays 17.6p a mile. At 35 mpg it is 22.7p and at 55 mpg 14.4p. A diesel car doing 55 mpg pays 16.5p a mile at 199.7p a litre.
How much petrol do I need for 300 miles?
A 45 mpg car uses 30.3 litres (6.7 UK gallons) to drive 300 miles. At the UK average of 174.6p a litre that costs £52.92.
How many miles will £20 of petrol take me?
About 113 miles in a 45 mpg petrol car at today's UK average of 174.6p a litre. A car doing 35 mpg gets about 88 miles and one doing 55 mpg about 139.
How much is a gallon of petrol in the UK?
A UK (imperial) gallon is 4.54609 litres, so a gallon of unleaded costs £7.94 at today's UK average of 174.6p a litre. A US gallon is only 3.785 litres, which is why US mpg figures look lower: multiply a US mpg figure by 1.2 to get UK mpg.
How do I convert litres per 100 km to mpg?
Divide 282.48 by the litres per 100 km figure to get UK miles per gallon. For example, 6.3 litres per 100 km is 44.8 mpg. The same sum converts mpg back to litres per 100 km.
Where does the fuel price in the calculator come from?
It is the average of the current prices at the UK forecourts in our data (7,949 stations report unleaded), taken from the government's Fuel Finder service and retailers' open price feeds, and checked 29 September 2026 at 16:13 UK time. You can pick a nation, a city or the cheapest station, or type the price on your own receipt.
More from our fuel price data
Sources and assumptions
- Fuel prices: 7,949 stations report unleaded and 8,060 report diesel in our data, from the government's Fuel Finder service (Open Government Licence v3.0) and retailers' open price feeds, checked 29 September 2026 at 16:13 UK time. "Cheapest station" ignores prices far below the local median, which are more likely to be reporting errors than bargains.
- UK gallon: 4.54609 litres (the imperial gallon). Distances use 1.609344 km to the mile.
- Default fuel economy: Typical real-world (not WLTP-sticker) fuel economy for mixed UK driving: WLTP figures usually overstate real-world economy by 15-25%.
- Electric comparison: the tariffs and efficiency of our EV running-cost calculator, checked 26 September 2026. Home rate: Ofgem energy price cap, Direct Debit GB average, 1 October to 31 December 2026 (ofgem.gov.uk). Public rapid charging: Zapmap EV Charging Price Index, weighted UK average for 50kW+ rapid/ultra-rapid chargers, pay-as-you-go, August 2026 (zapmap.com).
The arithmetic is shown in the questions above so you can check it. Fuel used depends on speed, load, weather and how you drive, so treat the result as an estimate. See about our data for how coverage is measured.