Simplified mileage and actual vehicle costs are alternatives for the costs they cover. Keep business-mile records and previous-claim history before choosing. Do not add fuel and running costs to a mileage deduction for the same use or switch methods simply to maximise one year’s claim.
Keep both the business facts and the vehicle history
Provide the vehicle type, purchase or lease details, business use and any private use. Tell the accountant about previous capital allowances or deductions. Prior treatment can restrict simplified mileage claims.
A mileage record should show enough detail to explain the business journeys. Receipts remain useful for reviewing actual costs and other relevant expenses. Travel between home and a normal workplace needs particular care.
Do not decide from fuel spending alone
Fuel is only one part of a vehicle’s cost, and a flat-rate method is not calculated by simply reimbursing fuel receipts. The accountant should compare the relevant evidence and rules for the tax year.
If you use several vehicles, identify them separately. Avoid combining miles and costs in one total with no explanation of which vehicle was used.
Choose consistently and keep the evidence
Ask how the selected method affects later years before switching. A method that appears attractive for one period may not be freely changeable afterwards.
Example: one cost, two possible approaches
A vehicle used for business and privately needs a method that fits the rules and its history. A mileage calculation and fuel receipts may help a comparison, but they are not automatically two deductions for the same journeys.
Can I switch methods whenever the result looks better?
Do not assume so. Previous claims and rules for the vehicle can restrict the options. Give the accountant earlier calculations before changing anything.
What does a useful journey record include?
Keep dates, business purpose and mileage in a consistent form. Explain the start and end points where needed. An annual total with no supporting trail can be difficult to review, especially where normal commuting and business travel have been mixed together.
Next step: Give TaxSimba your mileage evidence, vehicle documents and previous return calculations so the treatment can be reviewed before the figures are approved.
Use the rate for the right year and vehicle
HMRC’s published simplified rates distinguish the years: for cars and goods vehicles, the first 10,000 business miles use 45p a mile before 6 April 2026 and 55p for 2026/27; miles above that use 25p. Motorcycles use 24p. Eligibility and previous claims still matter. For illustration, 8,000 eligible car miles in 2025/26 give £3,600 at 45p—not the following year’s £4,400 at 55p. Do not apply these car rates to a bicycle.
Check the home nation used for your tax calculation
Tell the accountant whether you live in England, Scotland, Wales or Northern Ireland, and about any moves during the tax year. Scottish rates differ for wages, pensions and most other taxable income; savings and dividends use UK rules. Welsh rates are set separately. Use the rules for the relevant year and your actual taxpayer status.
See Scottish Income Tax and Welsh Income Tax. These differences do not make a London address or an England-only earnings example appropriate for everyone.
Recover last year’s vehicle method first
Illustrative preparation example.
Before comparing this year’s mileage and bills, locate the earlier vehicle claim and purchase history. A larger number from a new calculation does not establish that switching is allowed. Keep eligible business-mile records and actual costs so the permitted method can be checked.
Check: Which method is already in use for this vehicle, and which tax-year rates apply?
| Check | Practical action |
|---|---|
| Is the journey genuinely business travel? | Record purpose and route; distinguish normal commuting and personal use. |
| What has been claimed for this vehicle before? | Provide prior expense and capital-allowance calculations before considering a switch. |
| Would the claim duplicate running costs? | Apply the chosen method consistently and check any separately permitted items. |
Can I switch methods every year to whichever is larger?
Not necessarily. The vehicle's history and the method's rules can restrict later choices. Check before changing.
Is fuel spending enough to prove business mileage?
No. Keep a journey log and business purpose. Fuel receipts alone do not establish which miles qualify.
Download a checklist for this guide
- List each vehicle and acquisition details.
- Keep dated business journey logs.
- Record private use and commuting separately.
- Collect actual running-cost evidence.
- Locate earlier claims and confirm the available method.