Dental Practice Capital Allowances: How a £40K Chair Saves £18K in Year-One Tax

The short answer: what dental equipment actually qualifies

If you can lift it, plug it in or wheel it across the surgery, it almost certainly qualifies for capital allowances. The technical phrase HMRC uses is plant and machinery, and the legislative source is the Capital Allowances Act 2001. Inside a dental practice that means dental chairs, dental delivery units, dental cabinets, autoclaves, surgical lights, CBCT and OPG x-ray units, intraoral scanners, CAD CAM milling units, compressors, suction units, ultrasonic scalers, curing lights, instruments, computer equipment, practice management software and even the staff room kitchen if it is used wholly for the business.

The mechanism that makes this commercially attractive is the Annual Investment Allowance, usually shortened to AIA. AIA gives you 100 percent first-year relief on qualifying expenditure up to a £1 million cap per accounting period. The cap rose from £200,000 to £1 million in January 2019 as a temporary measure and was made permanent in the March 2023 Budget. For 2025/26 the £1 million is still in force, and it is enough to cover almost every routine equipment refresh a UK dental practice ever does in a single year.

The relief works against taxable trading profit. For a dental partnership that means the partners' share of allowable expenditure reduces the partnership profit, which then drops the income tax and Class 4 NIC each partner pays through Self Assessment. For a limited company, the relief reduces taxable profit before corporation tax. Same mechanism, different tax rate behind it. We come back to which structure benefits most in section four.

For the official position, see HMRC's guidance on the Annual Investment Allowance.

The £40,000 chair worked example

Take a real scenario we onboarded last quarter. A two-partner private dental practice in a London suburb, profits around £180,000 each. The senior partner buys a new A-dec 500 chair package for £42,500 plus a new intraoral scanner for £6,800. Both bought outright on 1 February 2026, both brought into use before the partnership year end on 31 March 2026.

Total qualifying spend: £49,300. All sits inside AIA. All gets 100 percent year-one relief. The partnership profit falls by £49,300 in the year. The senior partner's share of that reduction is half, so £24,650.

At her marginal rate (£100,000 to £125,140 income, which is the 60 percent effective band because of the personal allowance taper, then additional rate at 45 percent over £125,140), the partner saves close to £11,500 of income tax plus Class 4 NIC of around £490. Total saving for her alone: roughly £12,000 on a £24,650 share. Across both partners, the total cash tax saving is in the region of £22,500 to £24,000 against £49,300 of investment.

The reason the headline says "£18K on a £40K chair" rather than the lower textbook 47 percent number is the personal allowance taper. The taper bites between £100,000 and £125,140 of adjusted net income, taking the marginal rate up to about 60 percent for that £25,140 slice. For high-earning dental partners caught by the taper, a chunky AIA claim shifts you out of it, which is where the disproportionately large saving comes from.

Cars, vans and where capital allowances stop helping

The single biggest source of dental client confusion is cars. A dental principal who has just put £18,000 of relief through on a new chair often assumes the same logic applies to the practice car. It does not.

Cars are specifically excluded from AIA by section 38B Capital Allowances Act 2001. The relief route is writing down allowances based on CO2 emissions, applied to the main rate pool or the special rate pool depending on the band:

• Zero emission cars, new and unused: 100 percent First Year Allowance. This is the only car that effectively matches AIA. The 100 percent FYA on new zero emission cars is currently extended to 31 March 2026 for companies (corporation tax) and 5 April 2026 for unincorporated businesses (income tax), with the government having confirmed an extension to 2026/27.
• Cars with CO2 emissions up to 50g/km: Main rate pool at 18 percent writing down allowance per year on a reducing balance.
• Cars over 50g/km: Special rate pool at 6 percent writing down allowance per year on a reducing balance.

For the petrol family hatchback in our worked example, £40,000 of qualifying car spend yields just £7,200 of writing down allowance in year one (£40,000 at 18 percent). That cuts taxable profit by £7,200 not £40,000. At 47 percent marginal that is around £3,384 of tax saving in year one, with the rest dribbling out across the remaining writing down balance for the next decade.

Vans, double-cab pickups bought before 1 April 2025 (corporation tax) or 6 April 2025 (income tax), commercial vehicles and motorcycles all sit on the favourable side of the line and do qualify for AIA. Double-cab pickups bought from those dates are treated as cars for capital allowances and benefit in kind purposes following the April 2025 reclassification, which knocked them out of the AIA. If your associate dentist is sniffing around a Toyota Hilux, the post-April 2025 maths is very different from the pre-2025 maths.

Sole trader, partnership or limited company: does the structure change the maths?

The AIA mechanism is identical in all three. The relief eligibility, the £1 million cap and the qualifying assets are the same. What changes is the rate of tax sitting behind the relief, and that changes how big the cash saving actually is.

For an unincorporated dental practice (sole trader or partnership), the £49,300 of AIA in our worked example saves between 28 percent and 60 percent depending on which marginal band each partner sits in, plus 2 percent Class 4 NIC across the relevant slice. A partner sitting cleanly in the additional rate band saves roughly 47 percent across the relief. A partner caught by the £100,000 to £125,140 taper saves around 60 percent on that specific slice. A partner mostly at basic rate with a few thousand creeping into higher rate saves blended somewhere around 28 to 30 percent.

For an incorporated dental practice the same £49,300 reduces taxable profit before corporation tax. At a profit level of around £180,000 the company sits in the marginal rate zone, paying an effective 26.5 percent on the next pound of profit. That saves roughly £13,000 on the £49,300, rather than the £22,500 the unincorporated equivalent saves. The full saving comes through eventually as dividends or salary are extracted, but the headline year-one saving is lower in the limited company case.

This is a separate question from whether to incorporate at all. For more on that, see our sole trader versus limited company at £50K analysis. The short version for dental practices: incorporation makes sense once profit comfortably exceeds £100,000, the practice has multiple principals or associates, or the founder wants to extract less than full profits each year. Equipment purchases never tip the decision on their own.

Hire purchase, finance lease and the timing trap

How you fund the equipment can quietly destroy the AIA claim if no one looks at it. The three common routes for a dental practice are outright purchase, hire purchase, and finance lease. They behave very differently.

Outright purchase is straightforward. The chair is yours from day one, AIA applies in full, and the relief lands in the period in which the asset is brought into use.

Hire purchase preserves the year-one AIA claim as long as the contract is signed and the equipment is brought into use before the year end. HMRC treats hire purchase as if you paid the full cash price on day one, so a £42,500 chair on a five-year HP plan delivered and commissioned on 25 March 2026 still gets 100 percent AIA in the 2025/26 partnership period. You then claim the interest charges as a separate trading expense each year as the instalments fall due.

Finance lease is the trap. Under a finance lease the asset stays on the lessor's books, not yours. AIA does not apply. You claim the rental payments instead, as ordinary trading expenses spread over the life of the lease. For a £42,500 chair on a five-year finance lease at typical rates, that is roughly £9,000 to £10,000 of expense per year for five years. The total relief comes out similar over the long run, but the year-one cash tax saving is around £4,500 instead of £20,000. For a practice trying to manage a big payment on account or a known taper issue, the timing difference matters.

A practical tip: ask the equipment supplier upfront for an HP quote and a lease quote on the same chair. The wording on the agreement matters more than the badge. We have seen agreements branded as "lease" that legally functioned as HP and qualified for AIA, and others branded as "finance" that were genuine leases with no AIA. The legal substance, not the marketing label, is what HMRC tests.

Integral features and the practice fit-out

Buying or renovating the practice itself often involves spending tens or hundreds of thousands on the surgery shell. The building structure is not eligible for capital allowances at all. The integral features inside the structure are eligible, and a well-run cost segregation exercise typically pulls 25 to 45 percent of a surgery refurbishment out of the non-qualifying bucket and into qualifying pools.

What counts as an integral feature is defined by HMRC under list C of section 33A Capital Allowances Act 2001: hot and cold water systems, electrical lighting and power, ventilation, air-cooling and air-purification, lifts, escalators and external solar shading. For a dental surgery, the cumulative claim under this list is typically substantial because dental practices are heavy on bespoke lighting, dedicated electrical circuits for equipment, climate control to keep the surgery comfortable, and on multi-storey premises there are stair lifts or platform lifts to consider.

Integral features sit in the special rate pool at 6 percent writing down allowance per year on a reducing balance. Limited companies buying new and unused integral features can use the 50 percent First Year Allowance under the Full Expensing rules, which accelerates half the relief into year one. Unincorporated practices do not qualify for Full Expensing and rely on AIA up to the £1 million cap or 6 percent thereafter.

One specific opportunity that is regularly missed: practices that have done a major refit in the last two accounting periods can still claim missed allowances by amending the return. Beyond 12 months after the filing deadline, the relief is pushed onto the writing down balance and spread out across many years.

What this means for you: what to do before your year end

If you are planning equipment spend this year, the practical actions are clear and most of them are time sensitive.

1. Map your year end. A March year end with a January purchase has roughly two months to get the asset commissioned and in use. A January year end with a January purchase is dangerously close to the line.
2. Get the wording right on financing. Ask for an HP quote in writing. Confirm with the supplier whether the agreement passes legal ownership of the asset on day one (HP) or only at the end (true lease).
3. List the qualifying items. Do not just count the chair. The intraoral scanner, the surgery instruments, the new computer, the practice management software licence, and the staff room kitchen all stack into the same AIA claim.
4. Sense-check your marginal rate. If you are near the £100,000 or £125,140 thresholds, a chunky AIA claim can move you out of the personal allowance taper or out of additional rate, which compounds the saving.
5. Decide structure before the year you incorporate. If you are planning to incorporate in a future year, holding equipment purchases inside the unincorporated partnership often saves more cash tax than doing the same purchases through a new company.
6. Get a second opinion on past refurbishments. If a major refit happened in the last 12 months and the integral features were not separately analysed, an amendment may still be possible.

None of this is exotic planning. It is sequencing. Done at the right time it lands cleanly. Left to chance it disappears across a decade of writing down allowances or, in the worst case, lands in the wrong period and gets denied.