HMRC 24-Month Rule 2026/27: Temporary Workplaces & Mileage Claims Explained
The HMRC 24-month rule determines whether a workplace is “temporary” — and therefore eligible for tax-free mileage allowance — or “permanent,” where mileage is treated as ordinary commuting and cannot be claimed. Understanding this rule is essential for contractors, freelancers, and employees working at client sites.
Key Facts: HMRC 24-Month Temporary Workplace Rule
- ✓A workplace is temporary if you expect to attend it for less than 24 months
- ✓The 40% rule also applies — attendance must not exceed 40% of your working time at that location
- ✓Once either threshold is breached, the workplace becomes permanent and mileage claims stop
- ✓The 24-month clock resets if there is a genuine gap of at least one month with no attendance
- ✓Contractors at the same client site on consecutive contracts are assessed cumulatively
- ✓Approved mileage rate for cars in 2026/27: 55p/mile (first 10,000 miles), 25p/mile thereafter
What Is the HMRC 24-Month Rule?
HMRC defines a “temporary workplace” as any location where an employee or worker attends in the performance of their duties, and where attendance is not expected to be continuous for more than 24 months. Travel to and from a temporary workplace qualifies for the HMRC Approved Mileage Allowance Payment (AMAP) rates — currently 55p/mile for the first 10,000 business miles in a car or van.
Travel to a “permanent workplace” — including your regular office — is treated as ordinary commuting. Ordinary commuting costs cannot be claimed as a business expense and are not eligible for AMAP relief.
The legislation covering this is found in ITEPA 2003 s.339 (for employees) and the equivalent rules apply to the self-employed through ITTOIA 2005.
Two Conditions for a Temporary Workplace
Both conditions must be met. Failing either one makes the workplace permanent.
Duration: Less than 24 months
You must not expect to attend that workplace for a continuous period exceeding 24 months. The clock starts from the first day of attendance, or from the date it becomes clear that attendance will exceed 24 months.
Proportion: Less than 40% of working time
Your attendance at that workplace must not amount to more than 40% of your working time during the relevant period. Occasional visits don’t count — only regular, substantive attendance is assessed.
When the 24-Month Clock Starts — and When It Resets
Starting the clock
The 24 months is counted from the first day you attend the workplace, not from when you sign a contract. If it later becomes clear that your attendance will exceed 24 months — for example, because a contract is extended — the workplace is deemed to have become permanent from the very first day, not just from the extension date.
Important: Retrospective effect
If a contract extension pushes your expected attendance over 24 months, any mileage claims you made from day one at that site become potentially taxable. HMRC may seek to recover tax and NI on those claims.
Resetting the clock
A genuine break in attendance of at least one month or morecan reset the 24-month clock — but only if the break is real. Going on annual leave or a short absence doesn’t count. The break must be a substantive period where you are genuinely not attending that workplace.
HMRC scrutinises arrangements where workers take a short break then return to the same site claiming a fresh 24-month period. If the break looks artificial, HMRC can treat the attendance as continuous.
Worked Examples
Example 1 — Qualifies as temporary (claim allowed)
Sarahis an IT contractor working through her own limited company. She takes a contract at a client’s Manchester office from January 2026 to December 2026 (12 months). The contract ends and is not renewed.
The Manchester office is a temporary workplace. Sarah can claim 55p/mile for all business travel to that site throughout the contract.
Result: Full AMAP mileage relief applies — no issue.
Example 2 — Becomes permanent (claim must stop)
James is an umbrella company contractor placed at a client site from June 2024. His initial contract was for 18 months. In October 2025, his contract is extended for a further 18 months — taking expected attendance to 36 months total.
From October 2025 (the date it became clear attendance would exceed 24 months), the client site is no longer temporary. Worse, HMRC deems it to have been permanent from June 2024 — day one. All mileage claims from that date are affected.
Result: Mileage claims from June 2024 onwards are at risk. Tax and NI may be owed.
Example 3 — Borderline: 40% attendance rule
Priyais an employee who works two days per week at a client site and three days per week at her employer’s head office. She has been at the client site for 28 months.
Although she has exceeded 24 months, her attendance is only 40% of her working time (2 out of 5 days). The 40% rule applies — whether 40% is exceeded is measured by actual working time, not calendar time. This is a grey area requiring careful calculation.
Result: Seek advice. At exactly 40%, the threshold is breached — she must not exceed 40%.
The 24-Month Rule for Contractors and Umbrella Workers
Contractors working through a limited company or umbrella company are among those most affected by the 24-month rule. Key points:
- →Each client site is assessed separately: Working at Client A for 20 months then Client B for 20 months is fine — each is a separate temporary workplace, even if both are in the same city.
- →Cumulative contracts at the same site count: If you do a 12-month contract at a client, take 3 weeks off, then return for another 20 months — that's 32 months cumulatively. The short break is unlikely to reset the clock.
- →IR35 doesn't change the rule: Whether you're inside or outside IR35, the 24-month rule applies to your travel. Being inside IR35 creates additional risk because your mileage claims may be assessed more strictly.
- →Umbrella workers: employer perspective: Your umbrella company is your employer. The temporary workplace rule applies in the same way — if your placement exceeds 24 months, you lose the right to claim tax-free mileage.
HMRC Approved Mileage Rates 2026/27
These are the rates you can claim tax-free for travel to a temporary workplace. They cannot be used for travel to a permanent workplace.
| Vehicle type | First 10,000 miles | Over 10,000 miles |
|---|---|---|
| Car or van | 55p | 25p |
| Motorcycle | 24p | 24p |
| Bicycle | 20p | 20p |
| Passenger supplement (per passenger) | 5p | 5p |
Car rate increased from 45p to 55p from 6 April 2026. Source: HMRC EIM31205
Approaching the 24-Month Threshold: What to Do
If you’re approaching the 24-month mark at a workplace, take these steps:
- 1
Calculate your exact start date
Count from the first day you attended that workplace — not from when your contract was signed. Add 24 months to get your threshold date.
- 2
Assess the 40% rule concurrently
Review how much of your working time is spent at each location. If attendance rises above 40% at the site, permanence kicks in even before 24 months.
- 3
Stop claiming mileage from the threshold date
Once the workplace becomes permanent, stop claiming HMRC mileage rates for travel to that location. Do not back-date claims beyond the threshold.
- 4
Inform your employer or umbrella
If your mileage is reimbursed by an employer or umbrella company, notify them of the change so they stop processing your mileage claims for that site.
- 5
Consider alternative tax relief
Once a workplace is permanent, you cannot claim mileage — but if you use a company car with fuel card, advisory fuel rates may still be relevant. For self-employed workers, check whether actual vehicle costs provide any relief.
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