Home Office Costs for Landlords

If you run your lettings admin from home, a fair proportion of your household running costs is an allowable expense against rental profit. Unlike a sole trader running a normal business, however, a landlord cannot use HMRC's simplified flat-rate home office allowance. You need to work out a genuine apportionment of actual costs instead, based on how much of your home, and how much of your time, the property business actually uses.

This guide explains why the simplified flat rate does not apply to landlords, how to apportion real costs fairly, and a Capital Gains Tax point worth knowing before you set up a dedicated office room.

Why the simplified flat rate does not apply

HMRC offers sole traders and partnerships of individuals a simplified flat-rate deduction for working from home, a fixed monthly amount based on hours worked, instead of calculating actual costs. This flat rate sits within the trading income rules and, while property business profit is calculated using many of the same trading income rules under a general import provision, the specific flat-rate home office relief is not one of the provisions carried across into property income. HMRC's own Property Income Manual guidance on this point describes only the apportionment method below, with no flat-rate alternative for a property business.

In practice this means a landlord genuinely running their letting business from home needs to work out a reasonable proportion of actual costs, rather than reaching for a fixed monthly figure the way a sole trader would for an unrelated trade run from the same house. The apportioned figure sits alongside your other allowable costs on the property pages of your return, covered fully in our landlord allowable expenses guide.

What you can claim

Where you genuinely use part of your home to run the property business, whether that is a dedicated room or simply a desk you work from regularly, HMRC accepts a claim for the extra costs this creates and, where the use is more than incidental, a proportion of the fixed running costs of that space. This typically includes:

• Heating and lighting, apportioned by the extra use the property business creates.
• Council tax and, if you rent rather than own your home, a share of your rent, apportioned by the space and time the business genuinely occupies.
• Household insurance, buildings or contents, to the extent it relates to the space used.
• Repairs to the specific area used, if directly attributable to the business use rather than general upkeep of the whole home.

The claim should reflect what the business use actually adds or occupies, not an arbitrary round number. If you occasionally do an hour of admin at the kitchen table, a modest claim reflecting that limited, shared use is defensible. If you have converted a spare bedroom into a dedicated office where you manage a sizeable portfolio for several hours most days, a larger, more clearly calculated proportion is reasonable.

How to apportion fairly

There is no single prescribed formula; HMRC's own guidance simply asks for a fair and reasonable basis, applied consistently. Common approaches include:

• Floor area basis. Work out what proportion of your home's total floor area the office space represents, then apply that percentage to relevant running costs such as heating, lighting and council tax.
• Room-count basis. If your home has, say, six main rooms and one is used for the business, a simple one-sixth apportionment is a reasonable starting point, though this is a blunter measure than floor area for rooms of very different sizes.
• Time-based adjustment. Where the room is not used exclusively for the business, for example it doubles as a guest room or occasional study, scale the room's proportion down further by the rough share of time it spends on business use versus other uses.

Worked example. A landlord's home has five similarly sized main rooms, one of which is used as an office for managing a portfolio of six properties most working days, alongside occasional non-business use in the evenings. Using a room-count basis, the office represents one-fifth of the home's main rooms, and the landlord estimates around 70% of the time spent in that room relates to the property business rather than other use. Applying one-fifth, then 70%, to £2,400 of annual heating and lighting costs and £1,800 of council tax for the year gives an allowable proportion of roughly £294 for heating and lighting and £252 for council tax, a total home office deduction of around £546 for the year. Keeping a short note of how these figures were reached is enough to support the claim if it is ever queried.

The Capital Gains Tax trap

Claiming that a room is used exclusively for the property business, with no private use at all, can restrict Private Residence Relief on that room when you eventually sell your home, since the room is treated as a business asset for part of the property rather than as part of your main residence. This is a genuine trade-off: a larger, cleaner deduction now for exclusive use, against a potential Capital Gains Tax cost on a room's worth of your home's gain when you sell, covered more generally in our capital gains tax on rental property guide.

Most landlords running a modest home office avoid this by keeping the space in mixed use, for example a spare room that is also genuinely used for guests or storage some of the time, rather than declaring it exclusively for the business. This slightly reduces the annual deduction but avoids creating a CGT problem on a sale that may be years away and is often not worth the trade-off for the relatively modest sums a home office claim usually generates.

Common mistakes

• Using the sole trader flat rate by mistake. The £10, £18 or £26 monthly figures often quoted online for working from home relate to a trading business, not a property letting business, and are not available to a landlord.
• Claiming an unapportioned share of large fixed costs. Mortgage interest or rent on your own home is a personal cost in the first instance; only a carefully apportioned, genuinely business-related share, if any, is relevant, and mortgage interest on your own home is not part of the Section 24 finance cost rules that apply to your rental properties.
• Declaring exclusive use without weighing the CGT consequence. A bigger deduction today is not always worth a restriction on your main home's tax-free status when you eventually sell.
• Not keeping a workings note. A short record of the floor area, room count or time estimate used is what turns a reasonable claim into a defensible one if HMRC ever asks how the figure was reached.

A modest, well-evidenced home office claim is one of the smaller entries on a typical Self Assessment return, but it is worth getting into the habit of calculating it properly each year, particularly once you are inside Making Tax Digital and updating your figures quarterly rather than reconstructing a year of admin time in one sitting the following January.

How PropMaps helps

PropMaps keeps a record of your recurring home office workings alongside your other property expenses, so the apportionment basis you used one year is easy to find and update the next, rather than being recalculated from scratch every Self Assessment season.

Disclaimer

This guide is general information for UK landlords, not tax advice. Check GOV.UK, HMRC's Property Income Manual, or a qualified adviser for your situation.