UK petrol to diesel price gap
UK petrol to diesel price gap stood at 20.33 Pence per litre in Aug 2026, according to GOV.UK official statistics. It is one of the indicators in the Domestic energy prices table (Value · Monthly), with a complete series running from Jan 1991 to Aug 2026. The complete series with an interactive chart, free to download.
This indicator in the Domestic energy prices table
| Indicator | 08-2026 | 07-2026 | 06-2026 | 05-2026 | 04-2026 | 03-2026 | 02-2026 | 01-2026 | 12-2025 | 11-2025 | |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Road fuel and crude oil | |||||||||||
| Petrol to diesel price gap | 20.33 | 13.81 | 21 | 28.61 | 34.06 | 18.4 | 9.84 | 9.22 | 9.37 | 8.96 | |
| Crude oil acquired by UK refineries (2025=100) | 115.81 | 135.67 | 168.06 | 171.01 | 143.87 | 98.1 | 94.63 | 89.64 | 92.88 |
Understanding UK petrol to diesel price gap
This analytical series measures the absolute cash or percentage spread between average retail petrol and diesel pump prices across the United Kingdom. It captures the shifting cost differential driven by divergent global refining economics, seasonal heating demand substitutions, and varying taxation impacts between spark-ignition and compression-ignition fuels. Unlike single-fuel indices, this indicator highlights the relative cost burden shifts faced by mixed vehicle fleets and motorists.
Interpreting this gap requires recognising that historic pricing hierarchies can invert during periods of severe middle-distillate supply tightness. Monthly volatility in this spread reflects independent supply chain pressures rather than broad macroeconomic inflation trends. Analysts should examine pre-tax variants alongside this gross gap to determine whether retail margins or fuel duties are driving the divergence.
Frequently asked questions
- What does a widening petrol to diesel price gap indicate?
- It shows that diesel is becoming relatively more expensive compared to petrol at retail forecourts.
- Are taxes included in this price difference calculation?
- Yes, it is derived from standard gross pump prices that incorporate all duties and VAT.
- Does this cover filling stations across the entire United Kingdom?
- Yes, the geographic scope is nationwide.