CIS deductions and refunds, allowable tools, van and material costs, VAT reverse charge and MTD for Income Tax explained for UK self-employed kitchen fitters.
The tax position of a self-employed kitchen fitter is shaped by two things most office-based trades never deal with: the Construction Industry Scheme taking a slice of your labour before you ever see it, and a constant churn of tools, materials and van costs flowing through the business. Get those two things right and the rest of Self Assessment is straightforward. Get them wrong and you either overpay for years or hand HMRC an interest-free loan you never reclaim.
This guide is built around how kitchen fitters actually work: a mix of CIS subcontract jobs for builders and direct supply-and-fit work for homeowners, heavy spend on power tools and consumables, a van that is central to the business, and material costs you often buy and re-bill. Track it properly as you go and the annual return becomes a tidy-up rather than a panic.
As a sole trader you pay Income Tax on profit, which is your total fitting income minus allowable expenses. For 2025/26 the personal allowance covers the first GBP 12,570, then you pay 20% to GBP 50,270, 40% to GBP 125,140 and 45% above, with the personal allowance tapering away between GBP 100,000 and GBP 125,140 to create an effective 60% band. Class 4 National Insurance is 6% on profit between GBP 12,570 and GBP 50,270 and 2% above, with Class 2 NIC settled through Self Assessment.
Scottish fitters pay Scottish Income Tax on profit through six bands (19%, 20%, 21%, 42%, 45% and a 48% top rate) and carry an S-prefixed tax code, while National Insurance stays UK-wide. Welsh fitters have a C-coded tax code at rates currently matching the rest of the UK. If your code looks wrong, perhaps because CIS deductions or a part-time PAYE job are distorting it, run it through the tax code checker.
If any of your kitchen fitting is done as a subcontractor for a building contractor, property developer or main contractor, it falls within the Construction Industry Scheme. Under CIS the contractor must verify you with HMRC and deduct tax from the labour element of your invoice before paying you. The deduction is 20% if you are CIS-registered and 30% if you are not, which is the single best reason to register the moment you start subcontracting.
Two points trip fitters up. First, the deduction only applies to labour, so split your invoices clearly into labour and materials, because the contractor should only deduct from the labour line. If you lump everything together, you risk having tax deducted from your material costs too. Second, work done directly for a private homeowner is outside CIS entirely, so no deduction is made on that income and you account for the whole amount yourself.
Because CIS skims 20% off your labour before your personal allowance, tools, van and material costs are taken into account, it almost always over-collects. When you file, the GBP 12,570 tax-free band and your real expenses reduce your actual liability, and the CIS already paid is set against it. For most fitters the result is a refund. Our full CIS subcontractor guide walks through registration, statements and reclaiming, and the CIS tax calculator shows roughly what you are owed.
An expense is allowable when incurred wholly and exclusively for the business. For a kitchen fitter the list is dominated by tools, the van and materials rather than office costs.
| Expense | What qualifies | Notes |
|---|---|---|
| Power tools and hand tools | Drills, jigsaws, routers, track saws, planers, levels, clamps, tool boxes | Larger items via the Annual Investment Allowance, often claimed in full |
| Consumables and fixings | Blades, drill bits, screws, sealant, adhesive, abrasives, panel pins | Fully deductible as used |
| Van running costs | Fuel, insurance, road tax, servicing, repairs, tyres, breakdown cover | Or use simplified mileage at HMRC flat rates; pick one method per vehicle |
| Materials | Worktops, units, fixings and finishes you buy in | Deduct the cost; report the re-billed amount as income |
| Protective clothing and PPE | Safety boots, knee pads, gloves, goggles, ear defenders, dust masks | Branded work trousers and hi-vis qualify; everyday clothing does not |
| Insurance | Public liability, tools-in-transit and tool insurance | Essential cover for site and homeowner work |
| Waste and access | Skip hire, tip charges, parking and congestion charges on jobs | Ordinary commuting from home is not a job cost |
| Phone and admin | A fair business share of mobile and broadband, quoting software | Exclude the private share of dual-use costs |
| Trade and training | CSCS card, trade body fees, courses updating existing skills | Training into a brand-new trade is not allowable |
| Accountancy and bank fees | Bookkeeping, Self Assessment, business banking | Fully deductible |
The van is usually a fitter's largest running cost, and you choose one of two methods per vehicle. The simplified flat rate lets you claim a set amount per business mile with no need to total receipts, which suits a newer van with low repair costs. The actual-cost method claims a business proportion of every running cost (fuel, insurance, tax, servicing, repairs and tyres) plus capital allowances on the van itself, which usually wins for an older, higher-mileage van that needs work. Do the sum both ways once, keep a simple mileage log either way, and stick with your chosen method for that vehicle.
Where you supply units and worktops as well as fitting them, the material cost is a deductible expense and the amount you charge the customer for those materials is income. Record both. Netting them off, or only logging the fitting fee, understates your turnover, which matters for the VAT and MTD thresholds that are tested on gross income. Keep supplier invoices for every kitchen you buy in.
The private share of the van, phone and broadband must be excluded. Everyday clothing is never allowable even though you wear it on site; only protective and branded workwear qualifies. Meals on a normal working day are not deductible, and fines or parking penalties are never allowable. Tools bought before your trade started are pre-trading expenditure, claimed once you begin trading rather than ignored.
Take a fitter doing a mix of CIS subcontract work for two builders and direct supply-and-fit jobs for homeowners, with GBP 46,000 of income for the year, of which GBP 28,000 was CIS labour that had 20% (GBP 5,600) deducted at source.
Income: GBP 46,000 (CIS labour GBP 28,000, direct supply-and-fit GBP 18,000)
Allowable expenses:
Taxable profit: GBP 46,000 minus GBP 14,000 = GBP 32,000
Income Tax: GBP 32,000 minus GBP 12,570 = GBP 19,430 at 20% = GBP 3,886
Class 4 NIC: GBP 19,430 at 6% = GBP 1,166
Total tax and NIC: GBP 5,052. But GBP 5,600 was already deducted under CIS, so this fitter is owed a refund of around GBP 548, before any Class 2 NIC. Because CIS took 20% of labour before expenses and the personal allowance, the deductions exceeded the real bill. Run your own figures through the sole trader tax calculator to see where you land.
For a kitchen fitter, CIS is not your tax bill, it is a deposit on it. File on time, claim every tool and van mile, and HMRC usually owes you, not the other way round.
You must register for VAT once taxable turnover exceeds GBP 90,000 in any rolling 12-month period. Fitters who supply and install whole kitchens can reach this faster than they expect, because the value of the units and worktops you buy in and re-bill counts towards turnover, not just your labour. Keep a running 12-month total so registration does not catch you out.
Once VAT-registered, a second rule kicks in for construction work. The VAT domestic reverse charge applies when you do CIS construction work for another VAT-registered business that is not the end user. Instead of charging VAT and collecting it, you state on the invoice that the reverse charge applies, the contractor accounts for the VAT, and you receive only the net amount. You still reclaim VAT on your own tools, materials and van costs, which for a labour-and-materials trade often results in a VAT repayment. The reverse charge does not apply to work for private homeowners, where you charge VAT normally.
Keep digital or paper records of every invoice you raise, every supplier and tool receipt, your CIS payment and deduction statements, your mileage log, and your bank statements. The CIS statements are the documents that unlock your refund, so file them as they arrive rather than hunting for them in January. National Insurance comes in two parts: Class 4 at 6% then 2% on profit, calculated automatically, and Class 2, which is settled through your Self Assessment return and protects your State Pension and benefit entitlement. Even in a year where CIS deductions wipe out your Income Tax, paying Class 2 keeps your contribution record intact.
Making Tax Digital for Income Tax Self Assessment replaces the once-a-year return with quarterly digital submissions and a year-end finalisation. The thresholds are based on gross income, not profit:
For a supply-and-fit kitchen fitter the key trap is that the threshold is tested on gross turnover, which includes the materials you re-bill, so a fitter whose profit is modest can still be pulled in early by high material throughput. Instead of bundling a shoebox of receipts together each January, you record each invoice, tool purchase and CIS statement digitally as it happens and send HMRC a summary every quarter using MTD-compatible software. The upside is that the messy mix of CIS jobs and direct work becomes far easier to manage when it is captured continuously. Our guide to MTD for sole traders explains the quarterly rhythm.
Not registering for CIS. Failing to register means contractors deduct 30% instead of 20%, tying up even more of your cash until you file.
Not splitting labour and materials on invoices. CIS should only be deducted from labour. Lump everything together and you risk tax being taken from your material costs too.
Losing CIS statements. Those statements are the proof of tax already paid. Without them you cannot easily claim your refund, so file them month by month.
Netting off re-billed materials. Report the materials you charge customers as income and the cost as an expense. Hiding them understates turnover and distorts your VAT and MTD position.
Mixing the van methods. You cannot switch between simplified mileage and actual costs for the same van mid-life. Choose once and keep a mileage log either way.
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