If you've ever filled up your car and wondered why the price jumped 10p since last week — or dropped unexpectedly — you're not alone. Fuel prices are among the most volatile consumer costs, and understanding why they move can help you budget better and find cheaper fuel.
1. Global Crude Oil Prices
At the heart of every fuel price is crude oil. Brent crude and WTI are traded on global markets, and prices respond to supply and demand imbalances. OPEC+ production decisions, US shale output, and disruptions in major producing regions all move the needle. When crude rises, pump prices typically follow within 2-4 weeks.
2. Refining Costs and Margins
Crude oil must be refined into petrol and diesel. Refinery margins fluctuate based on seasonal demand (summer petrol blends are more expensive to produce), maintenance schedules, and geopolitical events affecting refinery output. In 2024-2025, several European refineries closed permanently, tightening supply and raising margins.
3. Government Taxation
Taxes are the single largest component of pump prices in most countries. In the United Kingdom, fuel duty (52.95p/litre) plus 20% VAT means tax accounts for roughly 55-60% of what you pay at the pump. Changes to fuel duty rates — even 1p — directly affect retail prices.
4. Exchange Rates
Since crude oil is priced in US dollars, countries with weaker local currencies pay more for the same barrel. A 10% fall in GBP/USD can add 3-5p per litre to UK pump prices over several weeks, even if crude prices stay flat.
5. Seasonal and Weather Factors
Summer demand for petrol rises due to holiday travel, pushing prices up. Winter diesel demand increases from heating and transport. Severe weather — hurricanes in the Gulf of Mexico, cold snaps in Europe — can disrupt supply chains and cause temporary price spikes.
6. Competition and Location
Local competition matters. Supermarket forecourts price aggressively to drive foot traffic, while motorway services and remote rural stations charge a premium. Prices can vary by 10-15p per litre within a 20-mile radius.
Summary
Fuel prices are determined by a complex mix of global markets, government policy, currency movements, and local competition. The best way to protect yourself is to monitor trends using our live price tracker, shop around, and consider fuel-efficient driving habits. Check our fuel saving tips for practical ways to cut your bill.