Everything a sole-trader window cleaner needs to know about tax, claimable expenses and Making Tax Digital in 2025/26.
Unlike most of the trades that share your high street, you will never have a contractor deduct 20% from your invoice before you see a penny. Window cleaning sits entirely outside the Construction Industry Scheme (CIS), which means the money lands in your account in full every time. The flip side is that no tax has been paid on your behalf, so the bill at the end of the year is entirely yours to plan for. The good news is that the combination of a capital-heavy kit list and relentless daily mileage gives you a genuinely strong set of deductions, if you know how to use them.
As a sole trader you pay Income Tax on your profits, which is your total income minus your allowable expenses. On top of Income Tax you pay Class 4 National Insurance Contributions (NICs). For 2025/26 the key thresholds are:
| Threshold or rate | 2025/26 figure |
|---|---|
| Personal Allowance (no tax) | GBP 12,570 |
| Basic-rate Income Tax (20%) | GBP 12,571 to GBP 50,270 |
| Higher-rate Income Tax (40%) | Above GBP 50,270 |
| Class 4 NIC rate (on profits GBP 12,570 to GBP 50,270) | 6% |
| Class 4 NIC rate (on profits above GBP 50,270) | 2% |
| Trading Allowance (optional, instead of expenses) | GBP 1,000 |
The trading allowance is almost never worth using if you run a proper round. Your actual expenses will far exceed GBP 1,000, so always claim real costs.
This is where your return is won or lost. HMRC allows you to deduct expenses that are wholly and exclusively for the purpose of your trade. For a window cleaner, that means a very specific kit list that most generic tax guides do not even mention.
| Expense | What to claim | Notes |
|---|---|---|
| Water-fed pole (WFP) system | Full purchase cost via Annual Investment Allowance | Claim in the year you buy it, not spread over time |
| Purification unit and DI resin | Full cost | Consumable or capital depending on value |
| Ladders, squeegees and scrapers | Full cost | Tools of the trade, fully deductible |
| Detergents and cleaning fluids | Full cost | Regular consumable |
| Van purchase or lease | AIA (purchase) or lease payments | Van is not a car for HMRC purposes; 100% business use is straightforward to argue for a dedicated round van |
| Van running costs: fuel, servicing, insurance, tyres | 100% of business proportion | Keep a mileage log; if the van is purely for work, the full cost is deductible |
| Mileage (if using your own car instead of a van) | 45p per mile for the first 10,000 miles, 25p thereafter | Use the HMRC mileage rate calculator to work out your deduction accurately |
| Public liability insurance | Full premium | Essential for both residential and commercial clients |
| Round-management software (e.g. Squeegee, CleanerPlanner) | Subscription cost | Fully deductible as a business software cost |
| Work clothing and PPE | Cost of branded or safety clothing | Must be distinctly work-related; ordinary clothes are not deductible |
| Water and power for the purification system | Business proportion of utility bills | Apportion if used at home; keep meter readings or supplier invoices |
| Mobile phone (business use proportion) | Business proportion of contract or bills | A dedicated work SIM is simpler and 100% deductible |
| Accountancy and bookkeeping software | Full cost | TapTax subscription counts here |
A good WFP system, including the pole, hose reel, trolley and purification unit, can easily cost GBP 2,000 to GBP 6,000 or more for a professional setup. Under the Annual Investment Allowance, you can deduct the entire purchase price from your taxable profit in the year you buy it. A window cleaner with GBP 28,000 profit who buys a GBP 3,500 system reduces taxable profit to GBP 24,500, saving roughly GBP 700 in tax at the basic rate. Do not let an accountant or software talk you into spreading that deduction over five years unless you specifically have a reason to.
A window cleaner covering a fixed weekly round drives the same streets day after day, and that mileage adds up fast. If you do 150 miles a day across a five-day week, that is around 7,500 miles a month and 90,000 miles a year. A dedicated round van is not a car in HMRC's eyes, which matters enormously: there is no private-use restriction on vans the way there is on cars, so 100% of genuine business running costs are deductible.
If you use a car rather than a van, you cannot claim actual fuel and running costs; instead you claim the HMRC approved mileage rates. Use the mileage rate calculator to see how quickly those journeys translate into a real tax deduction.
Window cleaning is a standard-rated service for VAT purposes, but the vast majority of solo operators running a single residential or mixed round turn over well under GBP 90,000 a year. You only need to register for VAT when your taxable turnover in the previous 12 months exceeds GBP 90,000, or when you expect to exceed it in the next 30 days.
Where VAT becomes relevant is when you take on commercial contracts, hire staff and effectively run a multi-van operation. At that point your turnover can climb quickly. Monitor your 12-month rolling total, because missing the registration date means HMRC can charge VAT on past sales as if you had been registered, which is a painful retrospective bill.
Take a sole-trader window cleaner turning over GBP 30,000 in 2025/26 on a fixed residential and light commercial round.
| Item | Amount |
|---|---|
| Gross income | GBP 30,000 |
| Van running costs (fuel, servicing, insurance) | GBP 4,200 |
| WFP system purchased this year (via AIA) | GBP 3,500 |
| Public liability insurance | GBP 400 |
| Detergents, DI resin and consumables | GBP 350 |
| Round-management software subscription | GBP 180 |
| Work clothing and PPE | GBP 150 |
| Mobile phone (business proportion) | GBP 240 |
| Total allowable expenses | GBP 9,020 |
| Taxable profit | GBP 20,980 |
On GBP 20,980 of profit:
Without the WFP system deduction (if incorrectly spread over years), taxable profit would be GBP 24,480 and the bill would rise to roughly GBP 2,887, a difference of GBP 700. Use the sole trader tax calculator to run your own numbers.
A water-fed pole system claimed through the Annual Investment Allowance cuts your tax bill the same year you buy it, not drip by drip over years of depreciation.
Making Tax Digital for Income Tax Self Assessment (MTD for ITSA) replaces the annual Self Assessment tax return with quarterly digital submissions to HMRC. The mandation timetable is:
Most window cleaners running a single round sit below GBP 50,000, meaning April 2027 is the relevant date for many in this trade. But the point is to start now. Quarterly submissions mean you need digital records of every invoice raised and every expense paid, updated regularly rather than reconstructed in January.
The TapTax guide to MTD for sole traders explains exactly what the submissions involve and how to prepare without the panic. The quarterly tax planner lets you spread your expected bill across the year so you are never caught short when a payment on account falls due.
This is the single most expensive mistake in the trade. A water-fed pole setup is plant and machinery for HMRC purposes. The AIA lets you deduct the full cost in the year of purchase, which can wipe thousands off your taxable profit immediately. Many window cleaners either miss the claim entirely or allow a bookkeeper to spread it as a depreciation charge, which is not the same as the AIA and results in a higher tax bill for years.
A dedicated round van with no private use is 100% deductible on running costs. If you also use it privately, you need to apportion costs honestly. The bigger mistake is claiming 100% with no mileage log to back it up; HMRC can and does challenge this, particularly if the van is your only vehicle.
Subscriptions to apps that manage your client list, schedule your rounds and handle invoicing are fully deductible business software costs. Many window cleaners pay for these every month and never record them on their return.
If you expand to multiple vans or take on large commercial contracts, track your rolling 12-month turnover. Missing the GBP 90,000 threshold is not a defence; HMRC will assess VAT from the date you should have registered.
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