Fuel Cost Calculator UK - Work Out Petrol, Diesel and Electric Costs Per Mile

Working out fuel costs before a journey can help with budgeting, commuting expenses and comparing running costs between petrol, diesel and electric vehicles.

Whether you need a fuel cost calculator, petrol cost calculator, diesel cost calculator, journey fuel cost calculator or a simple way to calculate fuel cost per mile, this guide explains how fuel costs are worked out and how to estimate the cost of everyday driving in the UK.

You'll also find practical examples for common journey distances, fuel usage calculations and cost-per-mile estimates to help you understand real-world running costs.

Fuel Cost Calculator UK

Calculate Your Fuel Cost in 3 Steps

1. Enter your journey distance.

2. Enter your vehicle MPG (or miles per kWh for an electric vehicle).

3. Use the latest fuel or electricity price to estimate your journey cost.

Fuel Cost Calculator Formulas

Vehicle Type	Formula
Petrol	(Distance ÷ MPG) × 4.546 × Petrol Price Per Litre
Diesel	(Distance ÷ MPG) × 4.546 × Diesel Price Per Litre
Electric	(Distance ÷ Miles Per kWh) × Electricity Cost Per kWh

This method can be used as a fuel calculator UK, petrol calculator, diesel calculator, mileage cost calculator or fuel use calculator.

Petrol Cost Calculator

A petrol cost calculator helps estimate how much a journey will cost based on distance, fuel economy and the current petrol price.

To calculate petrol costs:

1. Divide the journey distance by your vehicle's MPG.

2. Convert the result into litres using the UK gallon conversion factor of 4.546.

3. Multiply the fuel used by the current petrol price per litre.

Example: Petrol Cost for a 100-Mile Journey

A vehicle achieving 40 MPG travelling 100 miles would use approximately 11.4 litres of fuel.

If petrol costs £1.56 per litre:

11.4 × £1.56 = £17.78

This provides an estimated petrol journey cost before setting off.

Petrol Cost Per Mile

The petrol cost per mile formula is:

Petrol Cost Per Mile = (Fuel Price Per Litre × 4.546) ÷ MPG

This is one of the most common methods used to compare vehicle running costs.

Diesel Cost Calculator

A diesel cost calculator follows the same process but uses diesel fuel prices and diesel fuel economy figures.

Many drivers covering higher motorway mileage use diesel cost calculations when comparing vehicles.

Example: Diesel Cost for a 100-Mile Journey

A diesel vehicle returning 55 MPG would use approximately 8.3 litres of fuel over 100 miles.

If diesel costs £1.77 per litre:

8.3 × £1.77 = £14.69

This allows drivers to estimate diesel running costs before travelling.

Diesel Cost Per Mile

The diesel cost per mile formula is:

Diesel Cost Per Mile = (Diesel Price Per Litre × 4.546) ÷ MPG

Higher MPG figures generally result in lower fuel costs per mile.

Journey Fuel Cost Calculator

A journey fuel cost calculator helps estimate the total cost of a trip before travelling.

To work out journey fuel costs:

1. Find your vehicle's MPG.

2. Enter the journey distance.

3. Estimate fuel usage.

4. Multiply fuel used by the current fuel price.

Example: 50-Mile Journey Fuel Cost

Vehicle MPG	Estimated Fuel Used	Example Journey Cost*
30 MPG	7.6 litres	£11.86
40 MPG	5.7 litres	£8.89
50 MPG	4.5 litres	£7.02

*Using example petrol prices for illustration.

Example: 200-Mile Journey Fuel Cost

Vehicle MPG	Estimated Fuel Used	Example Journey Cost*
30 MPG	30.3 litres	£47.27
40 MPG	22.7 litres	£35.41
50 MPG	18.2 litres	£28.39

*Costs will vary depending on current fuel prices.

UK Fuel Prices Used for These Calculations

Fuel prices change regularly depending on region, retailer and market conditions.

For the most accurate result, use:

• Current local fuel prices

• Your vehicle's real-world MPG

• Typical driving conditions

• Actual journey distance

Using real figures will provide a more accurate fuel cost estimate than relying on national averages.

Fuel Cost Per Mile Calculator

Many drivers prefer calculating fuel cost per mile rather than total fuel spend.

The formula is:

Fuel Cost Per Mile = (Fuel Price Per Litre × 4.546) ÷ MPG

This can be used as a:

• Cost per mile calculator

• Price per mile calculator

• Pence per mile calculator

• Fuel cost per mile calculator

Petrol Cost Per Mile Example

If petrol costs £1.56 per litre and a vehicle achieves 40 MPG:

(1.56 × 4.546) ÷ 40

Estimated cost per mile = 17.7p

Diesel Cost Per Mile Example

If diesel costs £1.77 per litre and a vehicle achieves 55 MPG:

(1.77 × 4.546) ÷ 55

Estimated cost per mile = 14.6p

Electric Cost Per Mile Example

For electric vehicles:

Electric Cost Per Mile = Electricity Cost Per kWh ÷ Miles Per kWh

Charging at home is often significantly cheaper than using public rapid chargers.

Also Check: Super Unleaded vs Unleaded Petrol

Fuel Cost for Common UK Journey Distances

The table below shows how fuel costs increase as mileage rises.

Distance	Typical Fuel Cost Range*
25 miles	£3 to £7
50 miles	£6 to £15
100 miles	£12 to £30
200 miles	£24 to £60
500 miles	£60 to £150

*Actual costs depend on fuel prices and vehicle efficiency.

How Much Fuel Will I Use?

To estimate fuel usage:

Fuel Usage (Litres) = (Distance ÷ MPG) × 4.546

For example, a vehicle returning 40 MPG travelling 100 miles will use approximately 11.4 litres of fuel.

This calculation helps estimate:

• Fuel usage for a trip

• Monthly commuting costs

• Annual fuel expenditure

• Running costs when comparing vehicles

How Much Does Petrol Cost Per Mile in the UK?

The cost of petrol per mile depends on:

• Fuel price

• Vehicle MPG

• Driving style

• Traffic conditions

• Vehicle weight

• Journey type

More efficient vehicles generally have lower running costs than larger or less economical models.

How Much Does Diesel Cost Per Mile in the UK?

The cost of diesel per mile depends on:

• Diesel prices

• Vehicle fuel economy

• Annual mileage

• Driving conditions

• Motorway versus urban driving

Drivers covering longer distances often compare diesel and petrol running costs before choosing a vehicle.

Average Fuel Cost Per Mile UK

Average fuel cost per mile varies depending on:

• Petrol or diesel prices

• Vehicle efficiency

• Journey type

• Traffic conditions

• Vehicle load

Using a fuel cost per mile calculator provides a more accurate estimate than relying on general averages.

How Much Is a Gallon of Petrol and Diesel in the UK?

A UK gallon contains 4.546 litres.

To calculate the price per gallon:

Price Per Gallon = Fuel Price Per Litre × 4.546

Fuel Type	Calculation
Petrol	Price Per Litre × 4.546
Diesel	Price Per Litre × 4.546

This allows drivers to estimate the cost of a gallon of petrol or diesel using current pump prices.

Also Check: Petrol vs Electric Car Costs

Petrol vs Diesel vs Electric Running Costs

When comparing vehicle running costs, consider:

• Fuel costs

• Electricity costs

• Insurance

• Maintenance

• Vehicle tax

• Annual mileage

• Depreciation

Electric vehicles often provide the lowest energy cost per mile when charged at home, while diesel can remain cost-effective for drivers covering higher annual mileages.

Fuel Cost Per Mile and HMRC Mileage Rates

HMRC mileage rates are designed for mileage reimbursement and expense claims.

They are not the same as actual fuel cost calculations.

A fuel cost calculator helps determine real running costs, while HMRC rates are used for business mileage purposes.

Also Check: How Much Does It Cost to Charge a Tesla in the UK

Using Fuel Costs to Compare Cars Before Leasing

Understanding fuel costs can help drivers:

• Estimate commuting costs

• Compare petrol and diesel vehicles

• Compare electric vehicle running costs

• Budget for longer journeys

• Calculate monthly running costs

• Compare overall ownership expenses

For higher-mileage drivers, fuel efficiency can have a significant impact on annual running costs.

Also check below links:

• No Deposit Car Leasing – spread the cost without upfront payments

• Business Car Lease Deals – drive the affordable car with lower running costs

• Used Electric Car Leasing – affordable way to go electric