Fuel Cost Calculator
Calculate how much fuel your journey will cost. Enter distance, fuel efficiency, and fuel price.
How Fuel Costs Are Calculated
The formula is simple: Fuel Cost = (Distance / Fuel Efficiency) x Price per Litre. If you're driving 200 miles in a car that does 40 MPG, you'll use 5 UK gallons (22.7 litres). At £1.40/litre, that's £31.78.
The tricky part is fuel efficiency. The number on your car's spec sheet is measured in lab conditions — real-world MPG is typically 10-20% worse. Motorway driving, cold starts, heavy loads, and aggressive driving all reduce efficiency. Use your real-world figure for more accurate results.
To find your actual MPG: fill up completely, reset the trip counter, drive normally until you need fuel again, then divide the miles driven by the gallons used. Do this 2-3 times and average it. That's your real number.
Average Fuel Economy by Vehicle Type
| Vehicle Type | Official MPG | Real-World MPG | Cost per Mile (at £1.40/L) |
|---|---|---|---|
| Small hatchback (petrol) | 55-65 | 45-52 | 12-14p |
| Medium saloon (petrol) | 45-55 | 35-45 | 14-18p |
| SUV (petrol) | 35-45 | 28-38 | 17-23p |
| Small diesel | 65-75 | 50-60 | 11-13p |
| Hybrid (petrol) | 55-70 | 50-65 | 10-13p |
| Plug-in hybrid (short trips) | 100-200+ | 60-100+ | 6-11p |
| Electric (home charging) | N/A | 3.5-4.5 mi/kWh | 5-7p |
What this means for you: An electric car costs about 5-7p per mile on home charging vs 14-18p for a petrol saloon. Over 10,000 miles a year, that's £500-£1,100 in fuel savings. But public rapid charging narrows the gap to around 10-12p per mile.
UK Fuel Prices: Recent History
| Period | Unleaded (p/L) | Diesel (p/L) | Context |
|---|---|---|---|
| Jan 2020 | 127p | 132p | Pre-COVID baseline |
| Jul 2022 | 191p | 199p | All-time UK high (Ukraine crisis) |
| Jan 2024 | 143p | 152p | Prices stabilising |
| Jan 2026 | 140p | 148p | Current range |
What this means for you: Fuel prices are about 10% higher than pre-COVID levels. Supermarket forecourts (Asda, Sainsbury's, Tesco, Morrisons) are consistently 3-5p/litre cheaper than branded stations. Over a 50-litre fill-up, that's £1.50-£2.50 saved.
Ways to Reduce Your Fuel Bill
Check tyre pressure monthly
Under-inflated tyres increase rolling resistance and fuel consumption by 3-5%. Check pressures when cold and inflate to the manufacturer's recommendation (usually on a sticker inside the driver's door).
Drive smoothly
Aggressive acceleration and hard braking can increase fuel consumption by 15-30%. Anticipate traffic, coast to red lights, and stay in the highest gear possible. Cruise control helps on motorways.
Remove roof boxes when not in use
A roof box or rack increases aerodynamic drag. At motorway speeds, this can reduce MPG by 10-25%. Take it off between trips — the fuel savings add up fast.
Use supermarket fuel
All UK fuel meets the same BS EN 228 standard. Premium fuels offer marginal benefits for high-performance engines, but for most cars, supermarket fuel is identical in quality and 3-5p/litre cheaper.
Petrol vs Diesel vs Electric: Real Cost Per Mile
| Fuel Type | Cost Per Mile | Annual Cost (10,000 miles) | Notes |
|---|---|---|---|
| Petrol (40 mpg) | 16-18p | £1,600-£1,800 | Most common UK fuel type |
| Diesel (50 mpg) | 14-16p | £1,400-£1,600 | Better for motorway miles |
| Hybrid (55 mpg) | 12-14p | £1,200-£1,400 | Depends heavily on driving style |
| EV (home charging) | 5-7p | £500-£700 | Off-peak tariff assumed |
| EV (public charging) | 12-18p | £1,200-£1,800 | Rapid chargers cost more |
What this means for you: An EV charged at home overnight is the cheapest option by far — roughly a third of petrol costs. But if you rely on public rapid chargers, the savings shrink dramatically. The sweet spot for EVs is home charging with an off-peak energy tariff.
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Common uses
- Calculating the fuel cost of a specific journey
- Comparing fuel costs between different vehicles
- Estimating annual fuel expenditure for budgeting
- Working out cost per mile for business mileage claims
- Comparing petrol, diesel, and electric running costs
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