Tax Expenses & Relief · 2026
The Kitchen Table Claim: How to Get Tax Relief on Your Home Admin — Even Without a Dedicated Office
Quoting jobs, chasing invoices, logging receipts — if you do any of this at home, HMRC owes you money. Most CIS subcontractors have never claimed it. Here is exactly how much, and how to do it.
There is a persistent myth in the trades that 'use of home as office' only applies to people with a proper study, a separate room, and a desk with a view. It does not. If you do any business admin at home — on any surface, in any room — you are entitled to a tax deduction, and most subcontractors have been quietly overpaying for years by not claiming it.
Why HMRC Accepts This Claim for Tradespeople
Construction work happens on site. But the business behind it — the quotes, the invoices, the supplier calls, the CIS records, the Self Assessment prep — happens at home, in the evenings, at whatever surface is free. HMRC recognises this explicitly. You do not need a dedicated office room. You do not need a door that closes. You need evidence that you do genuine business work at home — which every subcontractor who runs their own books already has.
The claim is made under HMRC's 'Use of Home as Office' rules, which allow you to deduct a portion of your household running costs as a legitimate business expense. This reduces your taxable profit — and your tax bill — every single year.
You do not need a home office. You need a home where you do office work. For most subcontractors, that is already happening every evening of the week.
CIS Tax Insights, 2026Method 1: The HMRC Simplified Flat Rate
The flat rate is HMRC's deliberately simple option. No need to calculate actual bills or work out proportions. You track the number of hours you spend on business admin at home each month, pick the relevant band, and claim the fixed amount. That is it.
| Monthly Admin Hours at Home | Monthly Claim | Annual Claim | Tax Saved (20%) |
|---|---|---|---|
| 25–50 hours | £10 | £120 | £24 |
| 51–100 hours (most subcontractors) | £18 | £216 | £43 |
| 101+ hours | £26 | £312 | £62 |
With the flat rate, you only need a simple log of hours — a notebook, a spreadsheet, or notes on your phone. No bills required. A rough weekly estimate is sufficient: "Monday: 1 hour invoicing. Wednesday: 45 mins quoting." One month of records is enough to establish the pattern across the full year.
Method 2: Actual Costs — The Bigger Claim
If the flat rate feels underwhelming — and for most subcontractors in 2026 with high energy bills it should — the actual cost method calculates your real business share of household running costs. It takes slightly more record-keeping, but the numbers are meaningfully larger.
The formula is straightforward: identify your qualifying household costs, calculate what proportion of your home you use for business and for how long, and apply that percentage to each cost. The result is your deductible business expense.
What costs can you include?
Mortgage interest (not capital repayment), rent, gas, electricity, water, council tax, broadband, buildings and contents insurance — any cost of maintaining the home where the work happens. You cannot include the full amount; only the business-use proportion. But even a modest proportion of today's utility bills adds up to a meaningful claim.
Which Method Suits You?
The Five-Year Picture
Neither method creates dramatic annual numbers. But this is a claim you make every single year — and the compounded value over five years, never having been claimed before, is what makes the missed deduction genuinely costly.
recovered via lower tax bill
at 20% tax rate saving
pure overpayment
The Three Rules That Keep the Claim Clean
You cannot use the flat rate and actual costs for the same bills in the same year. Choose one method per tax year and stick to it. You can switch each April.
HMRC will not challenge a modest, defensible proportion. Claiming 50% of a household where you work 10 hours a week is not defensible. 10–15% usually is.
If a room is used exclusively for business, business rates may apply. Normal mixed-use admin work — kitchen table, living room — does not trigger this. Most subcontractors are not at risk.
Practical Checklist: How to Start Claiming This Week
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Start Logging Your Admin Hours Today Open a note on your phone or a spreadsheet. Every time you sit down to do business work at home — quoting, invoicing, bookkeeping, calls — log it. Even rough estimates are acceptable: "Monday evening, 1.5 hours." One month of records is enough to establish a credible annual pattern.
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Collect 12 Months of Household Bills Even if you plan to use the flat rate, keep your utility bills as backup. If you switch to actual costs later or your accountant recommends it, you will need them. Energy bills, broadband, council tax, buildings insurance — download them from your supplier portals now before older ones become inaccessible.
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Decide on Your Method Before the Tax Year Closes You cannot change method mid-year. If you are currently in 2025/26 and approaching April, decide now which route gives you the better claim. Your accountant can model both in under ten minutes. Do not default to the flat rate simply because it is easier without checking the actual cost figure first.
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Check Your Last Self Assessment Look at your most recent return. Is there a use of home claim? If not, you can amend the previous tax year if you are still within the four-year window. If your accountant prepared the return and the claim is missing, ask explicitly why — it may be a simple oversight that can be corrected before the amendment window closes.
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Check Your Mortgage or Tenancy Agreement Some mortgage lenders and landlords restrict commercial use of a residential property. For normal admin work this is almost never an issue — but it is worth a quick check. If there is a restriction, it typically applies to customer-facing use, not occasional bookkeeping. Your accountant can advise if you are uncertain.
Quick Decision: Which Method Is Right for You?
- You do under 25 hours of admin at home per month
- You want zero additional paperwork
- Your household bills are low or heavily shared
- You are just starting out and want to establish the habit of claiming first
- You do 10+ hours of admin at home per week
- Your energy and utility bills are high (above UK average)
- You also manage employees or run multiple jobs simultaneously from home
- You want to maximise every legitimate deduction on your Self Assessment
Stop Leaving It on the Kitchen Table
This is one of the most consistently underclaimed expenses across all of self-employment in the UK. Not because it is obscure or complicated — but because most tradespeople assume it does not apply to them, or that the numbers are too small to bother with.
They are not. Over five years, the actual cost method can put £1,500–£2,000 back in your pocket that you were never legally required to pay. The flat rate takes five minutes to set up and requires nothing more than a rough hour log. There is genuinely no reason not to claim.
Check your last return. If the claim is missing, fix it. Start logging your hours this week. And make sure your accountant includes it when they prepare the next one.
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This article is for informational purposes only and does not constitute professional tax or financial advice. Always consult a qualified accountant for advice specific to your circumstances. Flat rate figures based on HMRC Simplified Expenses guidance 2026/27. Actual cost estimates are illustrative and will vary by individual circumstances.