Fuel Consumption & HMRC Tax Rules

Calculating your vehicle's fuel consumption is a fundamental aspect of understanding your motoring costs. Whether you're a private individual looking to budget better or a business owner managing fleet expenses, knowing how much fuel your car uses and how it's treated for tax purposes is crucial. This guide will delve into the methods for calculating fuel consumption and explore the various fuel rate options accepted by HMRC (His Majesty's Revenue and Customs) for businesses in the UK.

Understanding Fuel Consumption

At its core, fuel consumption refers to the amount of fuel your vehicle uses to cover a specific distance. The most common way to express this is in miles per gallon (MPG) or litres per 100 kilometres (L/100km). A higher MPG or a lower L/100km indicates better fuel efficiency.

How to Calculate Fuel Consumption Manually

While modern cars often display real-time fuel consumption, performing a manual calculation can give you a more accurate picture, especially for older vehicles or if you want to cross-reference the onboard computer's figures.

1. Fill your tank: Visit a petrol station and fill your fuel tank completely. Note the mileage on your odometer.
2. Record your journey: Drive your car as you normally would. Keep track of your mileage.
3. Refuel again: When you next need to refuel, fill the tank completely again. Note the exact amount of fuel you've added (e.g., 45 litres) and the new odometer reading.
4. Calculate the distance: Subtract the initial odometer reading from the final odometer reading to find the distance travelled since the last fill-up.
5. Calculate MPG: Divide the distance travelled (in miles) by the amount of fuel added (in gallons). For example, if you travelled 350 miles and added 10 gallons, your MPG is 350 / 10 = 35 MPG.

Official Fuel Consumption Figures

New cars sold in the UK are subject to official tests like WLTP (Worldwide Harmonised Light Vehicles Test Procedure) and RDE (Real Driving Emissions). These tests are designed to provide more realistic fuel consumption and CO2 emission figures than older methods. WLTP tests are conducted in laboratory conditions, simulating a variety of driving scenarios, while RDE tests measure emissions in real-world driving conditions.

Fuel Costs and HMRC

For businesses, the treatment of fuel costs, particularly when vehicles are used for both business and private purposes, is a key consideration for tax purposes. HMRC provides specific guidelines on how businesses can account for these costs. The fundamental calculation for fuel cost is:

Fuel cost = Fuel consumption x Fuel price

The complexity arises when determining the deductibility of VAT and how to account for the private use of fuel.

Options for Treatment of Road Fuel Costs (Business Vehicles)

When a business pays for road fuel, HMRC offers four primary options for treating these costs:

Option A: 100% Business Use

If a vehicle is used exclusively for business purposes, such as a pool car that is not assigned to any particular employee, the business can treat all of the VAT paid on fuel as input tax. This means the VAT can be reclaimed.

Option B: Company Cars or Mixed Use Vehicles

This option applies to company cars, stock-in-trade cars, taxis, and private hire cars that are used for both business and private purposes. There are two sub-options here:

• Fuel Scale Charge: Businesses can opt to pay a fixed annual 'fuel scale charge'. This charge is designed to represent the VAT on the estimated private use of fuel. The scale charges are updated annually by HMRC. This simplifies accounting as you don't need to track every mile for private use.
• Account for VAT on Amounts Charged to Employees: Alternatively, if the business charges employees for the private use of fuel, it can account for output tax based on the amount actually charged to the employee. This requires accurate record-keeping of fuel provided for private journeys.

It's important to note that if the business chooses this option, they can choose between applying the fuel scale charge or accounting for output tax on the amounts charged to the employee. The fuel scale charges are subject to change, so it's essential to refer to the latest HMRC guidance for the relevant accounting periods.

Option C: Detailed Mileage Records

If a business prefers not to use the fuel scale charge, it can meticulously separate business mileage from private mileage. This method requires detailed record-keeping of all journeys undertaken in the vehicle.

Example Calculation:

Suppose a vehicle's total mileage for a period is 4,290 miles, with 3,165 miles being for business use. The total fuel cost was £368.

• Business Mileage Cost: £368 x (3,165 / 4,290) = £271.49
• Input Tax Claimable: £271.49 x (VAT Fraction)
• VAT Fraction: This is calculated as the VAT rate divided by (100 + VAT rate). For example, at 20% VAT, the fraction is 20 / 120 = 1/6. So, input tax = £271.49 x (1/6) = £45.25 (approximately).
• Private Mileage Cost: £368 x (1,125 / 4,290) = £96.51 (where 1,125 is the private mileage: 4,290 - 3,165).

HMRC may scrutinise calculations that differ from these methods to ensure that only the VAT relating to business use is reclaimed. The burden of proof lies with the business to demonstrate that private use is not being funded by the business. Cases like Phillips (G) VTD 12184 highlight the importance of robust record-keeping.

Option D: No Input Tax Claimed

In some scenarios, the amount of input tax that can be reclaimed might be less than the cost of the fuel scale charge. If a business finds that the total private and business mileage is low, and the scale charge would be more than the reclaimable input tax, they can opt to treat no VAT incurred on road fuel as input tax. This decision applies to all road fuel purchased by the business, whether for cars or commercial vehicles. A key benefit of this option is that the business will not need to account for output tax on the private use of the fuel.

Input Tax When Fuel is Purchased by Employees

When employees purchase fuel for business purposes and are reimbursed by their employer, the VAT on that fuel can be treated as input tax by the business. This is permissible provided the business can demonstrate that the employee was reimbursed either:

• Based on their actual expenditure.
• Through a mileage allowance.

Crucially, the business must obtain and retain appropriate VAT invoices for all fuel purchased by employees. While less detailed invoices might suffice in some cases, full VAT invoices are preferable. The input tax claim can only be based on the cost of fuel used for business purposes in making taxable supplies.

It's common for the value of fuel purchased by employees in a claim period not to perfectly align with the input tax claim. To ensure claims are supported, employers should encourage employees using their vehicles for business to retain all fuel invoices. This ensures that the value of business fuel used is covered by valid invoices at the end of the claim period.

Input Tax When Employees are Paid a Mileage Allowance

If employees are paid a mileage allowance for using their own vehicles for business, the input tax claimable by the business is calculated by multiplying the fuel element of the allowance by the VAT fraction. The allowance itself must be based on the actual mileage undertaken, and businesses must maintain records to substantiate this.

Essential records to keep for each employee claiming a mileage allowance include:

• Mileage travelled
• Whether the journey was for business or private purposes
• The cylinder capacity of the vehicle
• The rate of mileage allowance paid
• The amount of input tax claimed

HMRC officers may review the rates used by employers to calculate the claimable input tax on the fuel element of mileage allowances. Generally, rates published by motoring organisations like the AA or RAC are accepted. HMRC also provides its own advisory fuel rates, published twice a year, which are considered acceptable.

If an employer caps the mileage allowance paid to employees (e.g., paying a lower rate for vehicles with larger engines than they actually qualify for), HMRC will only allow input tax recovery based on the mileage rate actually paid to the employee.

Charges for Motoring Costs by Sole Proprietors and Partnerships

Sole proprietors cannot make a supply of fuel to themselves from their business. Therefore, they cannot avoid fuel scale charges by charging themselves for fuel used for private motoring. Partnerships, however, can make supplies to individual partners.

If a business funds private motoring, the fuel is considered an appropriation by the proprietor for personal use, and scale charges will apply. Sole proprietors can choose not to fund their private motoring through the business. In such cases, the business must demonstrate to HMRC that the input tax claimed relates solely to business mileage, typically by maintaining detailed mileage records.

Partly Exempt Businesses and Fuel Scale Charges

Partly exempt businesses, which make both taxable and exempt supplies, also need to consider how fuel costs affect their VAT recovery. They can treat VAT on fuel used for private motoring as input tax and declare scale charges. If the private use is separately identifiable and relates to a taxable supply (like the scale charge itself), the VAT is fully deductible. However, fuel use is often not known at the time of purchase, and business journeys may relate to exempt supplies, making fuel costs 'residual' for partial exemption calculations. This can lead to a restriction in the input tax that can be reclaimed.

In such circumstances, the fuel scale charge can be reduced to reflect the percentage of input tax that the business recovers under its partial exemption method. For instance, if a business recovers only 80% of its input tax, it would only pay 80% of the fuel scale charge.

When a partly exempt trader uses an output-values-based pro-rata calculation for non-attributable input tax, the tax-exclusive value of any fuel scale charges payable must be included in this calculation. The scale charge percentage also needs to be adjusted during the annual VAT return reconciliation.

VAT Groups and Scale Charges

For VAT groups, the concession of funding private motoring without claiming input tax must apply to the entire group registration. However, individual companies within the group may operate differently regarding the treatment of private motoring for other VAT purposes.

If a VAT group is partly exempt, the decision on whether to apply partial exemption calculations on a company-by-company basis or for the group as a whole depends on the group's chosen partial exemption method. If the partial exemption calculation is done globally, the same approach must be taken for fuel scale charges. Similarly, if the group uses a sectorised method, scale charges may be handled in the same manner.

When a Business Charges Employees for Private Fuel Use

If a business charges its employees for fuel used for private purposes at a price less than the cost value, the VAT incurred on that fuel is considered input tax. The business then has two choices:

• Apply the relevant fuel scale charge.
• Account for output tax based on the actual amount charged to the employee for the private use of the fuel.

Choosing the correct method for calculating fuel consumption and adhering to HMRC's guidelines on fuel cost treatment is vital for accurate financial reporting and tax compliance. Always consult the latest HMRC guidance or seek professional advice if you are unsure about your specific circumstances.

Frequently Asked Questions (FAQs)

Q1: How do I calculate my car's MPG accurately?

A1: The most accurate method is the manual 'pump-to-pump' calculation: fill your tank, note the mileage, drive until near empty, refill completely, and divide the miles driven by the gallons added.

Q2: What are WLTP and RDE figures?

A2: WLTP (Worldwide Harmonised Light Vehicles Test Procedure) and RDE (Real Driving Emissions) are testing procedures used to provide more realistic fuel consumption and emissions data for new vehicles compared to older methods.

Q3: Can I claim all the VAT on fuel if my car is only used for business?

A3: Yes, if a vehicle is used exclusively for business purposes (e.g., a pool car), you can treat all VAT paid on fuel as input tax and reclaim it.

Q4: What is a fuel scale charge?

A4: A fuel scale charge is an annual amount set by HMRC that businesses can pay to account for the VAT on the private use of fuel in company vehicles, simplifying the process compared to tracking every private journey.

Q5: Which mileage allowance rates does HMRC accept?

A5: HMRC generally accepts rates published by motoring associations like the AA or RAC, as well as HMRC's own advisory fuel rates, which are updated periodically.

Q6: What records do I need if I use the detailed mileage method?

A6: You need comprehensive records detailing all mileage, distinguishing between business and private journeys, along with vehicle details and fuel purchase information.

Q7: Can partly exempt businesses claim full input tax on fuel?

A7: Generally no, partly exempt businesses must apportion input tax based on their partial exemption method. Fuel scale charges may also be reduced proportionally.

Key Takeaways

Understanding these calculations and HMRC's rules ensures that businesses can accurately manage their vehicle running costs and comply with tax regulations. Proper planning and diligent record-keeping are paramount.