What expenses can a locum dentist claim? 2026/27 UK Tax Guide

Determining exactly what expenses can a locum dentist claim requires a strict application of the trading income rules. Locum and associate dentists typically operate as self-employed principals rather than employees.  Consequently, HMRC assesses their earnings as trading income derived from a profession or vocation.

For the 2026/27 tax year, locum dentists face a strict statutory test for every deduction, governed by the Income Tax (Trading and Other Income) Act 2005 (ITTOIA 2005), alongside significant new digital reporting mandates.

The General Rule: Wholly and Exclusively

Under section 34(1) of ITTOIA 2005, a self-employed dentist cannot deduct any expense in calculating their trading profits unless it is incurred “wholly and exclusively for the purposes of the trade”.  Where an expense serves a dual purpose (business and private), section 34(2) permits a deduction only for an identifiable part or proportion incurred exclusively for the practice.

Professional Fees, Indemnity, and CPD

Registration and Indemnity

Locums must hold registration with the General Dental Council (GDC) and maintain professional indemnity insurance to practice legally. Because these costs are a direct necessity for the trade, the premiums and fees satisfy the wholly and exclusively test and are fully deductible from trading profits.  Similarly, subscriptions to professional bodies like the British Dental Association (BDA) are allowable.

Continuing Professional Development (CPD)

Dentists must undertake CPD to maintain their clinical registration. HMRC’s Business Income Manual (BIM42526) confirms that expenditure on training is an allowable revenue expense if it updates existing expertise or acquires knowledge to keep pace with technological advancements in the existing business area.  HMRC specifically notes that the costs incurred by doctors and dentists in achieving professional revalidation are allowable.

“Costs incurred on training to acquire new skills or knowledge to keep pace with advancements in technology and changes in industry practices, related to the owner’s existing business area, will usually be allowable.”

(Note: If a dentist pays for training to acquire a completely new, unrelated medical specialisation, HMRC treats this as capital expenditure, which is not deductible as a revenue expense). 

Equipment and Dental Loupes (Capital Allowances)

Dentists frequently purchase high-value clinical equipment, such as bespoke dental loupes, handpieces, or portable curing lights. Because these items have an enduring benefit, they are treated as capital assets rather than day-to-day revenue expenses.

Under section 11 of the Capital Allowances Act 2001 (CAA 2001), self-employed locums can claim Plant and Machinery Allowances for capital expenditure incurred wholly or partly for their qualifying activity.  Typically, this allows the dentist to utilise the Annual Investment Allowance (AIA), meaning they can deduct 100% of the cost of the loupes from their taxable profits in the tax year of purchase.

Travel and Subsistence

Travel expenses are heavily scrutinised by HMRC, and the allowability depends entirely on the locum’s working pattern.

Ordinary Commuting (Disallowed)

If a locum dentist travels from their home to the same dental practice regularly, this constitutes ordinary commuting. The landmark High Court case of Sargent v Barnes confirmed that a dentist cannot deduct motor expenses for travelling from home to their surgery, even if they stop at a dental laboratory en route to pick up dentures.  The court held that such detours do not override the inherent private duality of travelling to or from the place the taxpayer chooses to live.

Itinerant Travel and Subsistence (Allowable)

Conversely, if a locum acts as a true itinerant worker—travelling to multiple different clinics irregularly to provide emergency cover—their travel costs between home and these temporary sites are allowable.

Furthermore, section 57A of ITTOIA 2005 grants a specific deduction for subsistence.  If the dental trade is itinerant by nature, the locum can deduct reasonable expenses for food and drink consumed at, or while travelling to, the practice.

The £1,000 Trading Allowance

For part-time locum dentists who incur very few expenses, section 783AD of ITTOIA 2005 offers a simplified alternative: the £1,000 Trading Allowance.  Rather than calculating the precise cost of travel, CPD, and uniform laundry, the dentist can elect to deduct a flat £1,000 from their gross trading income.  A dentist cannot claim both actual expenses (including capital allowances on equipment) and the Trading Allowance in the same tax year; they must evaluate which yields the higher deduction.

2026/27 Compliance: Making Tax Digital (MTD)

The 2026/27 tax year introduces a major shift in how locum dentists report these expenses. From 6 April 2026, the government mandates Making Tax Digital for Income Tax (MTD for ITSA) for self-employed individuals with a qualifying income of more than £50,000.

Locum dentists breaching this £50,000 threshold can no longer wait until January to file a single annual return. They must use MTD-compatible software to maintain digital records and send quarterly updates of their income and expenses to HMRC.  The subscription cost of this accounting software is fully deductible under section 34(1) ITTOIA 2005.

Summary of Locum Dentist Deductions (2026/27)

For completeness, if a locum dentist temporarily hires another professional (a locum substitute) to cover their shifts due to illness or maternity, the cost of paying that substitute is a fully allowable deduction against the principal dentist’s trading profits (BIM47125). 

Next steps: Review your self-employed clients’ gross income to determine if they breach the £50,000 threshold for the 6 April 2026 MTD mandation, and ensure their clinical equipment purchases are correctly tracked in compatible software to secure Annual Investment Allowances on their quarterly updates.