If you drive your own car for work and your employer pays you less than the HMRC approved mileage rate, you are probably leaving money on the table. The P87 form lets employees claim that difference back as Mileage Allowance Relief (MAR) without filing a full Self Assessment return.
After a brief postal-only period in late 2024, HMRC restored the online submission route in December 2024 through a new iForm. This guide covers exactly how the process works now, what evidence you need, and how to get your claim submitted as quickly as possible.
What Is the P87 Form and Who Can Use It?
The P87 (Tax relief for expenses of employment) is an HMRC form for employees on PAYE who need to claim tax relief on work-related expenses. The most common use is reclaiming mileage, but it also covers professional subscriptions, uniform costs, and tools.
You should use the P87 if:
- You are employed under PAYE (not self-employed)
- You do not already file a Self Assessment tax return
- Your total allowable employment expenses are £2,500 or less per tax year
- Your employer reimburses you less than 45p per mile, or pays nothing at all
If you already file Self Assessment, you claim the same expenses through your tax return instead. And if your expenses exceed £2,500 for a single tax year, you must register for Self Assessment and claim through that route rather than using the P87.
You can claim for the current tax year and the four previous years. For 2025/26, that means you can still go back to 2021/22 if you have not already claimed for those years.
What Changed: The October 2024 Evidence Requirements
In mid-2024, HMRC identified a growing number of ineligible P87 claims, in part driven by tax refund companies submitting claims on behalf of employees who did not actually qualify. HMRC responded in two ways.
First, from 14 October 2024, all P87 claims now require supporting evidence. Previously, HMRC often processed mileage claims without requesting proof upfront. That is no longer the case. When you submit a P87, you must provide documentation such as:
- A mileage log showing dates, start and end locations, business purpose, and distance for each journey
- Your employment contract or a letter from your employer confirming you are required to travel
- Evidence of any reimbursement your employer has already paid
The one exception is flat rate expenses (uniform cleaning, certain tools). These do not require evidence to be submitted with the form, though you must still be genuinely eligible.
Second, between 14 October and 22 December 2024, HMRC suspended the online P87 entirely. During that window, all claims had to be posted on paper. From 23 December 2024, HMRC relaunched the online route using a new iForm that includes an evidence upload facility.
The key point for 2025/26 and beyond: the evidence requirement is permanent. Keep thorough mileage records throughout the year, not just at claim time. Tripbook records every business journey automatically via GPS, so your mileage log is always ready when you need it.
How to Submit Your P87 Online (Step by Step)
The online iForm is available through your HMRC Personal Tax Account. Here is the process:
Step 1 — Sign in to Government Gateway Go to gov.uk/personal-tax-account and sign in with your Government Gateway credentials. If you do not have an account, you can create one using your National Insurance number and a form of identity verification.
Step 2 — Navigate to employment expenses From your Personal Tax Account, select the option to claim tax relief for employment expenses. Choose the tax year you want to claim for. You can submit a separate claim for each year, so if you are claiming for multiple years, complete them one at a time.
Step 3 — Enter your employer details Provide your employer’s name and PAYE reference number. You will find the PAYE reference on your payslip, P60, or P11D.
Step 4 — Enter your mileage details Input the total business miles driven in your own vehicle during the tax year, and the total amount your employer reimbursed you. HMRC calculates the shortfall automatically using the approved rates (45p for the first 10,000 miles, 25p thereafter).
Step 5 — Upload your evidence This is the step that did not exist before October 2024. The iForm now lets you upload digital copies of your mileage log, employment contract, or other supporting documents.
Step 6 — Review and submit Check the summary, confirm the details are correct, and submit. HMRC will either adjust your tax code for in-year claims or issue a repayment (by cheque or bank transfer) for prior-year claims.
Submitting by Post
If you prefer paper, or if an agent is submitting on your behalf (agents cannot use the online iForm), download form P87 from GOV.UK, complete it, attach your evidence, and post everything to:
HMRC Pay As You Earn BX9 1AS
Post takes longer to process, so the online route is strongly recommended where possible.
Processing Times: Online vs Post
How quickly you receive your refund or tax code adjustment depends on how you submit:
| Method | Typical processing time |
|---|---|
| Online iForm | 4 to 6 weeks |
| Post | 10 to 12 weeks |
For in-year claims, HMRC usually adjusts your tax code so that you pay less tax for the remainder of the year. For prior-year claims, you will receive a lump-sum repayment.
Processing times can vary depending on HMRC workload and the complexity of your claim. If HMRC needs to query your evidence, it will take longer. Submitting a clean, well-documented mileage log upfront is the best way to avoid delays.
How Much Tax Relief Can You Recover?
The amount you can claim depends on the gap between what your employer paid you per mile and the HMRC approved rate, multiplied by your business miles.
Example: 8,000 business miles, employer pays 20p/mile
- HMRC approved rate: 45p/mile (all under 10,000)
- Shortfall per mile: 25p
- Total claimable: 8,000 x 25p = £2,000
- Tax relief at 20% (basic rate): £400
- Tax relief at 40% (higher rate): £800
Example: 8,000 business miles, employer pays nothing
- Total claimable: 8,000 x 45p = £3,600
- This exceeds the £2,500 P87 threshold, so you would need to claim via Self Assessment instead
If your claim is close to the £2,500 limit, calculate carefully before deciding which route to use. For the rates and a worked calculator, see our guide to the HMRC mileage rate for 2026.
Keeping Mileage Records That HMRC Will Accept
Since October 2024, your mileage log is no longer just a backup in case HMRC asks questions. It is a required part of every P87 submission (except flat rate claims). Your log must include:
- Date of each journey
- Start and end locations
- Business purpose (e.g. client visit, site meeting)
- Miles driven
- Vehicle used (if you use more than one)
HMRC expects records to be kept for at least six years. Manual spreadsheets work but are easy to forget and tedious to maintain. Tripbook logs every journey via GPS tracking, categorises trips as business or personal, and lets you export a complete annual report in the format HMRC expects.
For a deeper look at what HMRC requires from your records, see our guide on business mileage record keeping for HMRC.
What If Your Claim Exceeds £2,500?
The P87 is only for claims of £2,500 or less per tax year. If your allowable expenses exceed that threshold, you must register for Self Assessment and claim through your tax return instead.
Common scenarios that push employees past £2,500 include high annual mileage with zero employer reimbursement, or combining mileage with other significant expenses like professional subscriptions.
If you are unsure whether your claim crosses the line, add up your total unreimbursed business miles at 45p (or 25p above 10,000) plus any other allowable expenses. If the total is under £2,500, use the P87. If it is over, see our guide on claiming mileage through HMRC Self Assessment.
Summary
The P87 online iForm is the fastest way for PAYE employees to claim mileage tax relief. Since December 2024, you can once again submit digitally through Government Gateway, but you now need to upload evidence with every claim. Keep accurate mileage records throughout the year, gather your employer details, and submit online for the quickest turnaround.
If you have not claimed for previous years, you could be owed a significant lump sum. The form takes around fifteen minutes to complete if your records are in order.
Download Tripbook from the App Store to build your HMRC-ready mileage log automatically.
