Live prices
Cheapest fuel on the M4
15 service stations on the M4 report through the official UK fuel price scheme, ranked cheapest unleaded first.
The cheapest reported unleaded on the M4 is £7.91 a gallon (173.9p per litre) at Rontec Magor near CALDICOT. M4 services average £8.66 a gallon (190.6p), 18.1p above the national average of 172.5p: filling 50 litres off the motorway typically saves about £9.05.
Prices last refreshed at 3:32pm on 20 September 2026, supplied through the official UK Government fuel price open data scheme.
| Grade | M4 average | National average | Difference |
|---|---|---|---|
| Unleaded (E10) | 190.6p (15) | 172.5p | +18.1p |
| Diesel (B7) | 212.2p (15) | 196.2p | +16.0p |
| Premium Unleaded (E5) | 207.9p (14) | 189.4p | +18.5p |
| Super Diesel (SDV) | 230.0p (14) | 215.2p | +14.8p |
Every M4 service station, cheapest unleaded first
| Station | Unleaded | Diesel | Premium | Super diesel | Updated |
|---|---|---|---|---|---|
 Rontec Magor (NP26 3YL)24hM4 Junction 23, Caldicot, Gwent | £7.91173.9p | £9.18201.9p | £8.81193.9p | £10.09221.9p | 32 mins ago |
 Rontec Cardiff West (CF72 8SA)24hM4 Junction 33, NR Pontyclun, Mid Glamorgan | £7.91173.9p | £9.18201.9p | £8.81193.9p | £10.09221.9p | 32 mins ago |
 Welcome Break Sarn Park (CF32 9SY)24hMotorway Services, Sarn, Brigend | £8.09177.9p | £9.09199.9p | £8.63189.9p | £9.63211.9p | 32 mins ago |
| Welcome Break Cardiff (CF23 8RA)24hMotorway Services, Cardiff Gate, Cardiff | £8.09177.9p | £9.09199.9p | £8.63189.9p | £9.63211.9p | 32 mins ago |
| Asda Pont Abraham Express Petrol (SA4 0FU)24hJ49 M4 Motorway, Llanedi | £8.50186.9p | £9.09199.9p | ---- | ---- | 32 mins ago |
| Leigh Delamere East Service Area (SN14 6LB)24hLeigh Delamere Service Area, M4, Chippenham, Wiltshire | £8.95196.9p | £9.91217.9p | £9.77214.9p | £10.72235.9p | 32 mins ago |
| Welcome Break Membury West (RG17 7TY)24hMotorway Services, Hungerford, Hungerford, West Berkshire | £8.95196.9p | £9.91217.9p | £9.50208.9p | £10.45229.9p | 32 mins ago |
| Reading West Connect Mwsa (RG30 3UQ)24hM4 Motorway Westbound, Reading, Berkshire | £8.95196.9p | £9.91217.9p | £9.91217.9p | £10.86238.9p | 32 mins ago |
| Heston East Service Area (TW5 9NB)24hHeston Service Area, J M Phoenix 2/3 M4, Phoenix Way, Houndslow, Middlesex | £8.95196.9p | £9.91217.9p | £9.77214.9p | £10.72235.9p | 32 mins ago |
| Chieveley Service Area (RG18 9XX)24hChieveley Service Area, M4 J13, Thatcham, Berkshire | £8.95196.9p | £9.91217.9p | £9.77214.9p | £10.72235.9p | 32 mins ago |
| Swansea Service Area (SA4 9GT)24hSwansea Service Area, M4 J47, Swansea, West Glamorgan | £8.95196.9p | £9.91217.9p | £9.77214.9p | £10.72235.9p | 32 mins ago |
| Leigh Delamere West Service Area (SN14 6LB)24hLeigh Delamere Service Area, M4, Chippenham, Wiltshire | £8.95196.9p | £9.91217.9p | £9.77214.9p | £10.72235.9p | 32 mins ago |
| Welcome Break Membury East (RG17 7TZ)24hMotorway Services, Hungerford, Hungerford, West Berkshire | £8.95196.9p | £9.91217.9p | £9.50208.9p | £10.45229.9p | 32 mins ago |
| Heston West Service Area (TW5 9NB)24hHeston Service Area, J M Phoenix 2/3 M4, Phoenix Way, Houndslow, Middlesex | £8.95196.9p | £9.91217.9p | £9.77214.9p | £10.72235.9p | 32 mins ago |
| Reading East Connect Mwsa (RG30 3UQ)24hM4 Motorway Eastbound, Reading, Berkshire | £8.95196.9p | £9.91217.9p | £9.91217.9p | £10.86238.9p | 32 mins ago |
Prices are supplied through the official UK Government fuel price open data scheme (Open Government Licence v3.0). Road matching uses motorway geometry from OpenStreetMap, © OpenStreetMap contributors (ODbL), and the station's own published details.
Leaving at a junction?
Prices a mile or two off the M4 are usually far cheaper. Search any postcode along your route.
More motorways
All motorway services pricesQuestions about M4 fuel
- Where is the cheapest fuel on the M4?
- The cheapest reported unleaded at a M4 service station is £7.91 a gallon (173.9p per litre) at Rontec Magor near CALDICOT. Prices were last refreshed at 3:32pm on 20 September 2026 from official UK Government fuel price data.
- How much more expensive is fuel on the M4?
- Across the 15 M4 service stations currently reporting unleaded, the average is £8.66 a gallon (190.6p per litre) against a national average of £7.84 (172.5p): 18.1p per litre more, about £9.05 on a 50-litre fill. Leaving at a junction usually beats filling at the services.
- Which stations count as M4 services?
- Stations flagged as motorway services in the official UK fuel price scheme, matched to the M4 by its road geometry (OpenStreetMap) or by the road named in the station's own published details.