Working from Home Tax Deductions — UK Sole Trader Guide for 2026

The two methods

HMRC offers two ways to claim home office costs as a UK sole trader:

Method 1 — Simplified flat rate No receipts needed. You claim a fixed monthly amount based on hours worked at home:

• 25-50 hours/month: £10/month (£120/year)
• 51-100 hours/month: £18/month (£216/year)
• 101+ hours/month: £26/month (£312/year)

Method 2 — Actual costs (use of home calculation) More complex but potentially higher deduction. You calculate the business proportion of actual household costs.

How to calculate actual home office costs

Step 1: Add up your total annual household costs — rent or mortgage interest, council tax, water, gas, electricity, buildings and contents insurance.

Step 2: Calculate the proportion attributable to your workspace. HMRC accepts two methods:

• Number of rooms: If you have 5 rooms and use 1 for business, the proportion is 20%
• Floor area: If your workspace is 15m² in a 100m² home, the proportion is 15%

Step 3: Calculate the time proportion. If you work from home 5 days a week for 10 months, the time factor is approximately 5/7 × 10/12 = 60%.

Step 4: Multiply: Total household costs × Room proportion × Time proportion = Allowable home office deduction.

Example: Annual household costs = £12,000. Room proportion = 20%. Time proportion = 60%. Allowable deduction = £12,000 × 20% × 60% = £1,440.

Compared to the flat rate method (£312/year for 101+ hours/month), the actual cost method delivers over £1,100 more in deductions.

The mortgage capital repayment issue

You can only deduct mortgage interest, not capital repayment. If you pay £800/month on your mortgage but £300 of that is capital repayment and £500 is interest, only the £500 interest element counts in your household cost calculation.

Renting is simpler — your full rent payment counts.

What else you can claim for your home office

Beyond the general household costs, you can also claim:

Broadband: A reasonable business proportion — typically 50-80% for home-based sole traders who use it primarily for business.

Mobile phone: The business-use proportion of your mobile contract.

Equipment: A laptop, printer, desk, or chair purchased specifically for business use. If the equipment is used partly personally, only the business proportion is allowable. A dedicated business laptop is 100% allowable.

Stationery and consumables: Paper, ink, pens — 100% allowable if for business use.

The capital gains tax risk with exclusive use

One important caveat: if you dedicate a room exclusively to business (it has no personal use at all), HMRC may argue that portion of your home was used as a business asset. On sale, you could lose Private Residence Relief on that proportion and face Capital Gains Tax.

Most home-based sole traders avoid this by ensuring their office space has at least some occasional personal use — using the room for occasional family activities, for instance. The simplified flat rate method carries no CGT risk at all.

Which method should you choose?

Run the numbers for your specific situation. If your household costs are high (renting in London, large energy bills), actual costs almost always win over the flat rate. If your costs are modest and your workspace is a small corner of the living room, the flat rate may be comparable and requires no receipts.

Once you choose a method, you can switch in future years, but it is cleaner to be consistent. Your bookkeeper can calculate the optimal method once they know your household costs.