You can use actual allowable home-working costs or simplified expenses where eligible. Simplified rates depend on hours worked at home; they do not include phone and internet. Compare the permitted methods and do not claim the same household cost twice.
Gather the facts before choosing a method
Tell your accountant which activities take place at home, how much time they take and what space is used. Keep relevant bills and explain whether rooms have both business and personal use.
HMRC permits an appropriate business allocation for certain home costs. Simplified-expense rules may also be relevant. Ask which approach is suitable rather than choosing a convenient percentage without evidence.
Keep phone and internet claims separate enough to understand
A shared connection or mobile plan needs consideration of private use. Paying the bill from a business account does not by itself establish that the whole cost relates to work.
Avoid unsupported calculations
A spreadsheet showing the calculation is useful when it connects back to bills and a reasonable method. Keep the explanation with the figures so it can be reviewed next year.
If you use part of the property exclusively for business or are considering significant changes to the arrangement, ask about wider consequences before acting. A routine expense claim should not accidentally become a property-tax planning decision.
Example: a room used for work and family life
Explain the hours and nature of business use, keep the bills and show the proposed allocation. The fact that a desk is in a room does not make every household cost a business expense.
Can I add a flat-rate claim to all the actual household costs?
Do not assume the methods can be stacked. Ask which costs the chosen approach covers and what needs separate consideration. Keep phone and internet treatment clear enough to avoid duplication.
What if the working pattern changes?
Update the explanation rather than automatically carrying forward last year’s percentage. Moving home, renting a workspace or reducing hours can change the evidence behind the calculation. The accountant should be able to follow the method from records rather than reconstruct it from memory.
Next step: Send TaxSimba the relevant bills and a short description of your working pattern. Your accountant can review the allowable amount as part of the agreed work.
Compare the monthly simplified rates
HMRC’s simplified home-working rates are £10 for 25–50 business hours a month, £18 for 51–100 and £26 for 101 or more. A qualifying 60-hour month therefore uses £18, not £18 per hour. Phone and internet are outside this flat rate: assess their business share separately. Compare with allowable actual household costs without claiming both for the same cost.
Check the home nation used for your tax calculation
Tell the accountant whether you live in England, Scotland, Wales or Northern Ireland, and about any moves during the tax year. Scottish rates differ for wages, pensions and most other taxable income; savings and dividends use UK rules. Welsh rates are set separately. Use the rules for the relevant year and your actual taxpayer status.
See Scottish Income Tax and Welsh Income Tax. These differences do not make a London address or an England-only earnings example appropriate for everyone.
Record hours as well as household costs
Illustrative preparation example.
For a representative month, note home-working hours and keep the relevant bills. Compare the eligible methods using the same period. Do not combine a simplified household-cost claim with the same actual household costs again. Phone and internet need their own assessment.
Check: What record supports the chosen method and prevents duplicate costs?
| Check | Practical action |
|---|---|
| How is the home used for the business? | Describe activities, space, hours and shared personal use. |
| Which calculation method fits? | Compare the permitted methods using actual evidence and avoid overlapping deductions. |
| Has the arrangement changed? | Update the basis after a move, new workspace or substantial change in working hours. |
Can I claim all rent or mortgage payments because I work at home?
No. The type of cost and reasonable business allocation need checking. Loan capital repayments do not become business expenses.
Is exclusive business use always preferable?
It can have wider consequences. Explain the actual use and seek advice before making property-use decisions solely for a deduction.
Download a checklist for this guide
- Describe the home-based activities.
- Record working hours and shared room use.
- Collect relevant household bills.
- Keep phone and internet use identifiable.
- Document the chosen method and any changed circumstances.