Fuel Cost Calculator

Q: How much does fuel cost per mile in the UK?

At March 2026 average prices, petrol costs approximately 18-20p per mile for a typical car doing 36 mpg at £1.45/litre. Diesel costs around 16-18p per mile at 43 mpg and £1.52/litre. Electric vehicles cost approximately 8p per mile on home charging (3.5 miles/kWh at 28p/kWh), rising to around 20p per mile on public rapid chargers.

Q: Is petrol or diesel cheaper to run?

Despite diesel costing more per litre, diesel cars typically have better fuel economy (around 43 mpg vs 36 mpg for petrol), making diesel cheaper per mile for higher-mileage drivers. The break-even point is typically around 10,000-12,000 miles per year. If you drive less, petrol is usually more economical overall.

Q: Is an electric car cheaper to run than petrol?

Yes, significantly cheaper for energy costs. A typical EV costs around 8p per mile on home charging vs 18-20p per mile for petrol — roughly 60% cheaper. Over 10,000 miles per year, that saves approximately £1,000-1,500 annually. However, EVs cost more to buy and public charging narrows the gap.

Q: What are the HMRC mileage rates for 2025/26?

The HMRC Approved Mileage Allowance Payment (AMAP) rates are 45p per mile for the first 10,000 business miles, then 25p per mile thereafter. These rates apply to cars and vans regardless of fuel type. Motorcycles receive 24p per mile and bicycles 20p per mile.

Q: How can I reduce my fuel costs?

Drive efficiently (gentle acceleration, steady speed) to improve MPG by 15-20%. Compare prices at supermarket forecourts vs branded stations. Maintain correct tyre pressure (3% improvement). Remove excess weight and roof boxes. Consider switching to electric if you drive over 10,000 miles per year and can charge at home.

Calculate the cost of any trip or your annual fuel budget. Compare petrol, diesel, and electric running costs. See your cost per mile and how it compares to HMRC mileage rates.

Calculate the fuel cost for a single trip

Trip distance

miles

One-way distance in miles

Fuel type

Fuel economy

mpg

Typical petrol: 30-40 mpg

Fuel price

£/litre

Check your local petrol station price

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How to Use This Calculator

Trip Cost tab

Enter your trip distance in miles, select your fuel type (petrol, diesel, or electric), and adjust the fuel economy and fuel price to match your vehicle. The calculator shows the total fuel cost, litres or kWh needed, and cost per mile. For business trips, it also compares your actual cost against the HMRC mileage allowance.

Annual Fuel Budget tab

Enter your annual mileage, fuel economy (mpg), and fuel price per litre. See your total annual fuel bill broken down by month, week, and cost per mile. The HMRC mileage allowance comparison shows whether the standard business mileage rate covers your actual fuel costs.

Petrol vs EV tab

Compare the annual running costs of your current petrol car against an electric vehicle. Enter both sets of efficiency and energy costs to see the annual saving. Add the EV price premium to calculate how many years until the fuel savings pay back the higher purchase price.

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The Formula

Fuel cost calculations convert distance and fuel economy into litres (or kWh) consumed, then multiply by the unit price:

Fuel needed (litres) = (Distance in miles ÷ MPG) × 4.546 litres per gallon

Trip cost = Fuel needed (litres) × Price per litre

Cost per mile = Trip cost ÷ Distance in miles

For EVs:
Electricity needed (kWh) = Distance in miles ÷ Miles per kWh
Trip cost = kWh needed × Price per kWh

HMRC mileage allowance:
First 10,000 business miles: 45p/mile
Above 10,000 miles: 25p/mile

The UK uses imperial gallons (4.546 litres), not US gallons (3.785 litres). MPG figures on UK car specifications are imperial. Always check whether your car's quoted MPG is the official WLTP figure (often optimistic) or your real-world average — real-world consumption is typically 10-20% higher than the manufacturer's claim.

For EVs, efficiency is measured in miles per kWh (or kWh per 100 miles). A typical modern EV achieves 3-4 miles per kWh, though this drops significantly in cold weather, at motorway speeds, or when using heating/air conditioning.

Example

Chris — Office Worker, 34, Birmingham

Chris commutes 30 miles each way (60 miles per day, 5 days per week) in a petrol car that averages 36 mpg. He takes 4 weeks of holiday per year, so drives 48 working weeks.

Annual commute calculation

Daily round trip60 miles

Working days per year240 (48 weeks × 5)

Annual commute miles14,400

Fuel economy36 mpg

Petrol price£1.45/litre

Gallons needed14,400 ÷ 36 = 400

Litres needed400 × 4.546 = 1,818

Annual fuel cost1,818 × £1.45 = £2,636

Monthly cost£220

Cost per mile18.3p

Chris spends £2,636 per year on his commute alone. If he switched to an EV doing 3.5 miles/kWh charged at home (28p/kWh), his annual electricity cost would be around £1,152 — saving £1,484 per year (£124/month).

HMRC mileage comparison

If Chris used his car for business travel, HMRC would reimburse: 10,000 × 45p + 4,400 × 25p = £4,500 + £1,100 = £5,600. Since his actual fuel cost is £2,636, the mileage allowance is meant to also cover insurance, depreciation, and wear.

FAQ

How much does fuel cost per mile in the UK? ▼

At March 2026 average prices, petrol costs approximately 18-20p per mile for a typical car doing 36 mpg at £1.45/litre. Diesel costs around 16-18p per mile at 43 mpg and £1.52/litre. Electric vehicles cost approximately 8p per mile on home charging (3.5 miles/kWh at 28p/kWh), rising to around 20p per mile on public rapid chargers at 70p/kWh. Your actual cost per mile depends on your car's real-world fuel economy, which is typically 10-20% worse than the manufacturer's official WLTP figure.

Is petrol or diesel cheaper to run? ▼

Despite diesel costing more per litre (approximately 7-10p more), diesel cars typically have better fuel economy (around 43 mpg vs 36 mpg for petrol). This means diesel is usually cheaper per mile for higher-mileage drivers. However, diesel cars tend to cost more upfront and have higher servicing costs. The break-even point is typically around 10,000-12,000 miles per year — if you drive less than this, petrol is usually the more economical choice overall. Diesel also attracts higher road tax in some London boroughs (ULEZ charges apply to older diesel vehicles).

Is an electric car cheaper to run than petrol? ▼

Yes, significantly cheaper for fuel/energy costs alone. A typical EV costs around 8p per mile on home charging vs 18-20p per mile for petrol — roughly 60% cheaper. Over 10,000 miles per year, that is approximately £1,000-1,500 in annual savings. However, EVs typically cost more to buy (£5,000-15,000 premium), may have higher insurance, and depreciation patterns differ. Public charging narrows the gap considerably. The total cost of ownership depends on how many miles you drive, whether you can charge at home, and how long you keep the car. For high-mileage drivers with home charging, an EV usually pays for itself within 5-7 years.

What are the HMRC mileage rates for 2025/26? ▼

The HMRC Approved Mileage Allowance Payment (AMAP) rates for 2025/26 are: 45p per mile for the first 10,000 business miles, then 25p per mile thereafter. These rates apply to cars and vans. Motorcycles receive 24p per mile, and bicycles 20p per mile. These rates are the same regardless of fuel type (petrol, diesel, or electric). If your employer pays less than AMAP rates, you can claim Mileage Allowance Relief (MAR) on the difference through Self Assessment. HMRC also publishes quarterly Advisory Fuel Rates for company car drivers, which vary by engine size and fuel type.

How can I reduce my fuel costs? ▼

The most effective ways to cut fuel costs: 1) Drive efficiently — gentle acceleration, maintaining steady speed, and anticipating traffic can improve MPG by 15-20%. 2) Compare prices — supermarket forecourts are typically 5-10p/litre cheaper than branded stations, and motorway services charge a premium. Use apps like PetrolPrices or Waze to find the cheapest local fuel. 3) Maintain your car — correct tyre pressure alone can improve fuel economy by 3%. 4) Remove excess weight and roof boxes when not in use. 5) Consider a more efficient car or switch to electric if you drive over 10,000 miles per year and can charge at home.

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