Allowable Expenses for the Self-Employed: The Complete HMRC Guide

A surprising number of sole traders pay more income tax than they need to, not because they are doing anything wrong, but because they are not claiming all the expenses they are entitled to. Equally, some claim expenses they should not, leaving themselves exposed in the event of an HMRC enquiry. Getting allowable expenses right is one of the most practical and immediate ways to reduce your tax bill legitimately.

This guide explains allowable expenses self-employed individuals can claim, how HMRC's rules work, which costs are commonly overlooked, and where the boundaries lie.

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The Core Rule: Wholly and Exclusively

Before examining specific categories of expense, it is essential to understand the overarching test that HMRC applies to all sole trader expenses. Under the Income Tax (Trading and Other Income) Act 2005, expenses are deductible only if they are incurred "wholly and exclusively" for the purposes of the trade.

This means that if an expense has a dual purpose — part business, part personal — it is generally not allowable in full. There are some exceptions where HMRC accepts an apportionment (splitting the cost to reflect the business proportion), but the starting position is strict. You cannot claim a family holiday as a business expense simply because you checked emails while you were away.

The practical implication is that documentation matters. Keeping receipts, noting the business purpose of expenditure, and maintaining clear records is not just good practice; it is your defence if HMRC asks questions. Self-assessment records should generally be kept for at least five years after the 31 January filing deadline for the relevant tax year.

From 6 April 2026, sole traders with qualifying income above £50,000 are required to use Making Tax Digital for Income Tax (MTD for IT), keeping digital records in compatible software and submitting quarterly expense updates to HMRC. Those with income above £30,000 join MTD from April 2027. The expense categories covered in this guide apply equally under MTD — the rules on what qualifies have not changed, but the way those expenses are reported to HMRC has.

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Office and Administration Costs

For most sole traders, day-to-day running costs form the backbone of their expense claims. These include stationery, postage, printing, ink, and similar consumables. Accounting software subscriptions, cloud storage fees, and telephone costs used for business are also deductible, as is the business portion of a mobile phone contract.

Sole trader expenses HMRC accepts in this category also include bank charges on business accounts, professional subscriptions to recognised trade or professional bodies, and the cost of trade publications relevant to your work.

One area that regularly generates questions is the use of a home as an office. If you work from home, you can claim a proportion of household running costs including heating, electricity, and broadband. HMRC offers two approaches: the simplified flat rate (currently £10 per month for 25 to 50 hours of business use per month, £18 for 51 to 100 hours, and £26 for 101 or more hours per month), or a calculated apportionment based on the number of rooms used exclusively for business and the proportion of time spent working there. Note that you must work at least 25 hours per month from home to use the simplified rate at all. The flat rate is simpler but often produces a smaller deduction than a carefully calculated apportionment.

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Travel and Vehicle Costs

Travel undertaken wholly for business purposes is deductible. This includes train tickets, bus fares, taxi costs, and parking fees incurred on business trips. Commuting — travelling between your home and a fixed regular workplace — is not allowable. However, as a sole trader your home is often your base of operations, meaning travel to client sites or temporary work locations is generally deductible.

For vehicle costs, HMRC permits two methods. The simplified mileage rate currently stands at 45p per mile for the first 10,000 business miles in a tax year, and 25p per mile thereafter. Using this method means you cannot additionally claim fuel, insurance, or maintenance; the flat rate covers everything. Alternatively, you can claim actual vehicle running costs apportioned to reflect business use, plus capital allowances on the vehicle's value.

Worked example:

Maria is a self-employed graphic designer who drives 8,000 miles for business purposes during the 2026/27 tax year. Using the simplified mileage rate:

8,000 miles × 45p = £3,600 deductible against her trading profits

Had she earned £35,000 in the year, this reduces her taxable profit to £31,400, saving her approximately £720 in income tax at the basic rate of 20%, plus a further saving on Class 4 National Insurance.

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What Can Self-Employed Claim for Staff and Subcontractors

If you employ staff or engage subcontractors, those costs are generally deductible. Wages, salaries, employer National Insurance contributions, and employer pension contributions for employees all reduce your taxable profits. Subcontractor fees are similarly deductible, provided the arrangement is genuinely a business-to-business relationship and not a disguised employment situation.

The distinction between employment and self-employment for the people you engage is a separate and important question. Getting it wrong can result in HMRC treating subcontractor payments as employment income, with significant PAYE and National Insurance consequences. If you regularly engage the same individuals, it is worth reviewing the working arrangements carefully.

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Stock, Materials, and Cost of Sales

If your business involves buying goods to sell on, or purchasing materials to use in your work, those costs reduce your taxable profit. This is straightforward for traders who buy and resell stock, but applies equally to tradespeople buying materials for jobs, caterers purchasing ingredients, or makers buying components.

The deductible amount reflects the cost of goods actually sold or used in the year, not simply everything purchased. If you have unsold stock at the year end, its value sits on your balance sheet rather than in your expense claim. Sole trader expenses HMRC accepts here must relate to actual business costs, not personal purchases routed through the business.

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Professional Fees and Financial Costs

Accountancy fees, bookkeeping fees, and the cost of professional advice directly related to your business are all deductible. This includes the cost of preparing your self-assessment tax return — the fee Blue Tick charges for tax return preparation is itself an allowable expense.

Legal fees incurred in the normal course of business, such as drafting client contracts or pursuing unpaid debts, are deductible. Legal costs relating to the purchase of a capital asset are not revenue deductible (they may be added to the asset's cost for capital gains purposes), and costs connected to personal matters remain disallowable.

Bank interest on business borrowings and finance charges on business loans are also allowable. The position on hire purchase and leasing arrangements depends on the structure of the agreement and whether the asset qualifies as plant and machinery for capital allowances purposes.

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How Blue Tick Can Help

Blue Tick works with self-employed individuals across a range of trades and professions to ensure their expense claims are both complete and defensible. From first-time sole traders unsure what qualifies, to established freelancers who want a structured review of their expenses, Blue Tick provides clear, practical guidance on what can self-employed clients claim to legally minimise their tax liability. Head to our website and book a meeting now.

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Putting It Into Practice

Getting your allowable expenses right as a sole trader comes down to three habits: recording everything with a clear business purpose noted, applying the wholly and exclusively test honestly before claiming, and reviewing your expense categories at least once a year to make sure nothing is being overlooked. The tax savings from a thorough and correct approach are real and repeatable year after year. If you are not confident your current expense claims are as complete as they could be, now is the right time to find out.

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This article is intended for general informational purposes only and does not constitute tax, legal, or financial advice. Tax rules are subject to change and their application will depend on your individual circumstances. You should always seek advice from a qualified professional before taking action. Blue Tick Accountants accepts no liability for decisions made on the basis of this content.