Home Working Expenses: Flat Rate vs Actual Costs for Sole Traders

The Two Methods at a Glance

HMRC allows sole traders and freelancers to claim a portion of their home running costs as a business expense. You must choose one of two approaches for each tax year: the simplified flat rate (often called the fixed rate allowance) or the actual cost method, where you calculate a genuine proportion of your real household bills.

The Simplified Flat Rate: Quick and Painless

From April 2024, HMRC updated the simplified expenses flat rates for home working. The rates are based on the number of hours you work from home each month:

• 25 to 50 hours per month: £10 per month (£120 per year)
• 51 to 100 hours per month: £18 per month (£216 per year)
• 101 or more hours per month: £26 per month (£312 per year)

If you work from home full time, you will almost certainly qualify for the top rate of £26 per month. This is simple to claim, requires no receipts, and HMRC will not challenge it. You simply include it on your Self Assessment return under allowable expenses.

The Actual Cost Method: More Work, Potentially More Relief

With the actual cost method, you calculate the proportion of your household bills that relate to your business use. The standard approach is to divide your costs by the number of rooms in your home and then apply a time-based percentage for business use.

For example, suppose your home has five rooms used equally, you work from one room, and you use it for business roughly 40% of the time (around eight hours out of a typical working day). Your calculation for an annual gas and electricity bill of £2,400 would look like this:

• £2,400 divided by 5 rooms = £480 per room
• £480 multiplied by 40% business use = £192 claimable for energy alone

You can apply the same logic to broadband, water rates, and even a proportion of your mortgage interest or rent. Add these together and the actual cost method can easily exceed the £312 annual flat rate, particularly if your energy bills are high or you occupy a small property with few rooms.

Which Method Works Best for You?

The flat rate wins on simplicity. If your home bills are modest, your property is large, or your business use of your home is low, the flat rate may actually deliver a similar or better result once you factor in the time taken to gather evidence. It is also completely audit-proof.

The actual cost method wins on value if you have high energy bills, a dedicated office room, or a smaller property where the room-based calculation produces a generous percentage. Many freelancers working full time from a two or three bedroom flat find the actual method yields two to three times the flat rate relief.

Key Rules to Keep in Mind

• You cannot claim mortgage capital repayments, only interest, and only proportionally. Be cautious here as this can affect Capital Gains Tax principal private residence relief when you sell.
• Keep records of your bills, bank statements, and a note of how you calculated your business use percentage in case HMRC asks.
• The simplified method is only available to sole traders, not limited companies. Directors must use a different approach entirely.
• You cannot mix the two methods within the same tax year.

A Practical Step to Take Now

Before you file your 2025 to 2026 Self Assessment return, total up your annual household bills and run the room and time calculation. Compare it against £312. If the actual method produces a higher figure, use it and keep your supporting records. If the difference is small, the flat rate may simply not be worth the paperwork. Either way, making an informed choice rather than defaulting to the flat rate is one of the easiest wins available to any freelancer working from home.