Tax, CIS and Making Tax Digital for self-employed kitchen and bathroom fitters

When Making Tax Digital starts for kitchen and bathroom fitters

It depends on your qualifying income, not your trade. Qualifying income is the total of self-employment and property income before expenses (turnover), not profit.

Once you’re in, you send HMRC a quarterly update by 7 August, 7 November, 7 February and 7 May, then a tax return after the year ends. MTD for Income Tax does not change how tax is paid or the payment due dates.

Check your own start date and what to sort first. It’s free and takes a minute.

CIS for kitchen and bathroom fitters

HMRC treats fitting a kitchen, bathroom or fitted bedroom furniture as an alteration to the building, so it is covered when a builder or developer pays you. Swapping a broken basin or tap on its own is a repair to a system and outside, and so is delivering units without fitting them. One contract that includes the fit brings the plumbing, wiring and tiling under it into CIS as well. Homeowners are not contractors, but if you pay another trade for construction work on a homeowner’s fit, you are the contractor and must run CIS on them.

When CIS applies, a contractor deducts 20% if you’re registered for CIS, 30% if you’re not, and nothing if you have gross payment status. To work out a CIS deduction, the contractor starts with the gross invoice and takes away what the subcontractor paid for VAT, consumable stores, fuel (except for travelling), plant hire, manufacturing or prefabricating materials, and materials; the CIS rate is then deducted from the amount left.

Before you join Making Tax Digital, over-deducted CIS is claimed back through your Self Assessment tax return. Once you are in Making Tax Digital, HMRC adds your CIS deductions to your tax return, and any refund is requested separately through HMRC online services. Either way, the sooner after 5 April the return is filed, the sooner HMRC can repay you.

Estimate your CIS refund

Free, and it runs in your browser: add your van or mileage, tools and phone, for 2025-26 and 2026-27.

Costs kitchen and bathroom fitters usually claim

The test for every cost is whether it was for your business. If something is partly personal, only the business part counts.

Your van, tools and kit

A fit can keep you at one house for a week or two before you move on, which HMRC usually treats as travel to temporary sites, so keep a note of where you worked. If you run the business from a showroom or unit, the trip from home to there is commuting, and travel from it to customers is business. The van has to take units and worktops; it is business equipment, and so are your jigs and power tools. A bigger van or a skip hired for one job is a running cost.

From 2024-25 the cash basis is the default for sole traders and partnerships without corporate partners, with no turnover limit; traditional (accruals) accounting is an opt-out. Under the cash basis, the cost of equipment bought to keep and use in the business, such as machinery, computers and vans, is claimed as a normal allowable expense rather than a capital allowance. Cars are different: they go through capital allowances.

Simplified expenses for cars and goods vehicles (vans) from 6 April 2026: 55p a mile for the first 10,000 business miles, then 25p; motorcycles 24p. Once used for a vehicle you must keep using it for that vehicle, and it cannot be used for a vehicle already claimed through capital allowances.