If you own your dental practice through a limited company and you pay tax at the higher or additional rate, while your husband or wife has spare basic-rate band or an unused personal allowance, employing your spouse can move some income into a lower-taxed pair of hands. Done properly it is a legitimate, long-established planning tool. Done carelessly it is one of the first things an HMRC enquiry unpicks. The line between the two is not a clever structure. It is whether the work is genuine and the pay is a market rate.

This guide is written for the incorporated practice owner, where a spouse goes on the company payroll and the salary is a corporation-tax deduction. If you are a self-employed associate or sole trader rather than a company owner, the principles overlap but the mechanics differ, and our guide to employing a spouse as a self-employed associate covers that position. Spouse pay is one lever inside the wider profit-extraction picture, so read it alongside how you take salary and dividends, not in isolation.

Why owners look at spouse employment

The logic is income-splitting within a household. Suppose you draw enough from the practice to sit firmly in the 40% band, while your spouse has little or no income of their own and a £12,570 personal allowance going unused, plus a basic-rate band taxed at 20%. Every pound of practice income you can legitimately route to the spouse instead of yourself is taxed once at their rate rather than at yours. Across a year the household keeps more.

That is the attraction, and there is nothing aggressive about it as a concept. Families share work and income, and the tax system does not require a married couple to ignore the fact that one of them does real work in the business. What it does require is that the arrangement reflects commercial reality. The moment the salary stops being a payment for genuine work at a sensible rate, and becomes a device to park income in the spouse's name, the deduction is at risk and the saving evaporates.

So treat spouse employment as a planning tool with a hard edge, not a free lunch. The rest of this guide is about staying on the right side of that edge.

The two tests that govern everything

Two conditions decide whether a spouse's salary is deductible against company profits, and both must be satisfied.

First, wholly and exclusively. A cost is deductible in computing trading profit only if it is incurred wholly and exclusively for the purposes of the trade. For a company that rule sits in section 54 of the Corporation Tax Act 2009 (the equivalent of section 34 ITTOIA 2005 for unincorporated traders). A salary paid for work that genuinely serves the practice meets it. A salary paid for no real work, or paid partly out of natural love and affection rather than for the trade, does not.

Second, the market-rate limb. Even where work is done, HMRC will look at whether the pay is commensurate with that work. Its own guidance, at BIM37740, addresses remuneration paid to family members and is blunt about the remedy: where the pay is excessive, HMRC will disallow the excess. It does not necessarily strike out the whole salary, but it removes corporation-tax relief on the part that exceeds a market rate. The classic example is a spouse paid far more than an unconnected employee would earn for the same role, where the extra is really a distribution of profit dressed as wages.

Put the two together and the rule is simple to state and harder to satisfy: the spouse must do real work the practice needs, and the pay must be no more than you would pay a stranger for that work. Get either limb wrong and you lose relief on some or all of the salary.

Genuine work: what a spouse can legitimately do

Dental practices generate a lot of non-clinical work, and much of it is exactly the kind of role a spouse can fill properly. The point is not to invent a job title. It is to identify work the practice genuinely needs and have the spouse actually do it. Common, defensible roles include:

  • Practice management, covering rotas, supplier relationships, premises and the day-to-day running of the business.
  • Bookkeeping and finance admin, raising and chasing invoices, reconciling the bank, preparing figures for the accountant.
  • HR and staffing, recruitment, onboarding, holiday and absence tracking, contracts and the people side of a growing team.
  • Marketing, the website, social media, patient communications, recall campaigns and local advertising.
  • Compliance and CQC administration, policy upkeep, audit support, decontamination-record oversight and the documentation a CQC-registered practice has to keep current.
  • Reception and patient coordination, where the spouse genuinely covers front-of-house hours.

The role must be real and needed, and the spouse must have the time and capability to do it. If your practice already employs a full-time practice manager, paying a spouse a second practice-manager salary for overlapping duties is hard to justify. If the practice has genuine unmet administrative need that the spouse fills, you are on solid ground. Describe the role as it actually operates, because that description is what you will be defending if HMRC asks.

Market rate: how to evidence it

Market rate means what an unconnected person would be paid for the same role and the same hours. It is a pounds-per-hour question, not a round number chosen to absorb the personal allowance. The difference matters because the second approach, picking a salary because it happens to equal an allowance, is precisely the fingerprint of an arrangement built for tax rather than for work.

Build the benchmark deliberately. Note the role, the hours per week, the responsibilities and the local going rate for comparable practice-manager, bookkeeping or administrative pay. Job adverts, recruitment-agency guidance and pay surveys all help. Then sense-check the result: if a part-time practice administrator in your area earns, say, £14 to £18 an hour, a spouse doing eight hours a week of genuine admin is worth roughly £6,000 to £7,500 a year, not £25,000. Keep the workings. A two-line note of how you arrived at the rate, dated and filed, is worth far more in an enquiry than a confident assertion after the fact.

The PAYE and RTI mechanics

A spouse salary is only real if it is run like a real salary. That means proper payroll, not a year-end journal.

  • Register as an employer with HMRC if the company is not already operating PAYE.
  • Run the spouse through payroll under RTI, with payslips and a Full Payment Submission to HMRC on or before each payday.
  • Operate PAYE and NIC correctly, deducting income tax and employee NIC where due and accounting for employer NIC.
  • Actually pay the money into the spouse's own bank account. A salary booked to a director's loan account or paid into the owner's account, and never genuinely received by the spouse, is a gift to an HMRC enquiry.

The cleanest cases are where the spouse is paid monthly, by standing order, into their own account, with an RTI trail that matches. The weakest are where the salary exists only as a single year-end entry with no payslips and no movement of cash to the spouse. The mechanics are not a formality. They are part of the evidence that the employment is genuine.

Employer NIC and the Employment Allowance trap

A spouse salary has an employer cost, and you must factor it into the saving. For 2025/26 the company pays employer (secondary) Class 1 NIC at 15% on earnings above the secondary threshold of £5,000 a year (the threshold was cut to £5,000 and the rate raised to 15% from 6 April 2025). On a £15,000 salary that is 15% of the £10,000 above the threshold, which is £1,500 of employer NIC the company has to pay on top of the salary itself.

You might expect the Employment Allowance to mop that up. It is £10,500 for 2025/26, and it does reduce a company's employer NIC bill. But it is not available to a company whose only employee paid above the secondary threshold is a single director. Many one-director dental companies fall exactly into that exclusion, which is one reason they often set the director's own salary at the secondary threshold rather than the full personal allowance. Adding a genuinely employed spouse above the threshold can take the company out of the single-director restriction and bring the allowance back into play, but the rules on connected and family employees are detailed and the eligibility position should be confirmed, not assumed. Do not build a plan on the allowance until you have checked it applies.

Salaried spouse versus shareholder spouse

There are two genuinely different ways to involve a spouse, and they answer to different rules.

Employment pays a salary for work done. It is deductible for the company, it must be market-rate, and it carries the PAYE, NIC and auto-enrolment obligations above. The constraint is the wage test.

A shareholding gives the spouse genuine ordinary shares in the company, on which dividends are paid out of post-tax profit. A dividend is not a payment for work, so it is not measured against a market-rate wage. Instead the relevant risk is the settlements legislation, which can attribute income back to the donor where one spouse gifts an income stream to the other. The leading case here is Jones v Garnett (the Arctic Systems case), in which the House of Lords held that an outright gift of ordinary shares between spouses, carrying full rights, fell within the inter-spouse exemption and was not caught. The practical lesson is that a genuine shareholding with normal rights is generally robust, whereas artificial structures, dividend waivers and alphabet shares whose only purpose is to divert income are where challenges land.

The two routes can co-exist. A spouse who does real work can hold a salary for that work and also hold shares as a genuine co-owner of the business. What you cannot do is use a salary to pay for work that is not done, or a shareholding to disguise what is really a reward for the owner's own labour. Match the route to the substance.

Worked example: the income-split saving when the rate is genuine

Take a higher-rate owner whose practice genuinely needs a part-time practice manager, and a spouse with no other income. A defensible market-rate salary for the role is £15,000 (2025/26 figures throughout).

The company side. The £15,000 salary is deductible against trading profit. At the 19% small-profits rate (profits up to £50,000) the deduction saves the company £2,850 of corporation tax; at the 25% main rate it saves £3,750. Against that, the company pays employer NIC of £1,500 (15% on the £10,000 above the £5,000 secondary threshold). So at the small-profits rate the net company cost of the salary, after CT relief and the NIC, is £15,000 plus £1,500 minus £2,850, which is £13,650.

The spouse side. A £15,000 salary uses the £12,570 personal allowance, then 20% basic-rate tax on the remaining £2,430, which is £486 of income tax. Employee NIC applies on earnings above the primary threshold as well. The spouse's overall tax cost on this income is modest, a long way below the owner's marginal rate.

The comparison. Had the owner instead extracted the same £15,000 from the company and taken it as a dividend, it would have come out of post-CT profit and been taxed in the owner's hands at the upper dividend rate of 33.75% (2025/26), before the rise to 35.75% from 6 April 2026. The household benefit of the spouse route is the gap between the owner's marginal cost of that income and the spouse's near-zero-to-basic-rate cost, after netting off the employer NIC. The saving is real, but it exists only because the role and the rate are real. Strip out the genuine work and the same numbers become a disallowed excess.

Worked example: employer NIC eats into the saving

It is worth isolating the NIC drag, because owners often forget it. On the same £15,000 salary, the £1,500 of employer NIC is a direct cost the company would not pay if it left the money in the business or extracted it as a dividend. If the company cannot use the Employment Allowance (the single-director restriction), that £1,500 stands. Netting it against the CT saving and the income-split gain is the honest way to see the true household benefit. A salary set too close to the point where the income-split gain barely exceeds the NIC plus the spouse's own tax is not worth the administrative effort, which is another reason to start from the genuine market rate rather than chase the personal allowance.

Worked example: the excessive-pay disallowance

Now the cautionary version. An owner pays a spouse £25,000 for roughly three hours a week of basic admin. On enquiry, HMRC accepts that the work is worth a market rate of around £4,000 and applies BIM37740 to disallow the £21,000 excess. The consequences stack up. The company loses corporation-tax relief on £21,000, so it owes the CT that relief had sheltered. The owner is exposed to additional tax at their marginal rate on the amount HMRC treats as really theirs. Interest runs on the underpaid tax from the original due date. And a behaviour-based penalty can apply, up to 30% of the tax for careless behaviour, higher if HMRC regards the arrangement as deliberate. The headline figure that looked like a saving turns into a bill plus interest plus a penalty. The £4,000 that reflected genuine work would have been fine; the £21,000 that did not was never going to survive.

Where HMRC challenges and what it costs

The pattern HMRC looks for is easy to describe. A large salary, a small amount of actual work, no payroll trail, payment into the wrong account, and a number that suspiciously equals a tax allowance. The "£20,000 for three hours of admin" arrangement is the archetype. The remedy is BIM37740: disallow the excess, leaving relief only on the market-rate part.

The cost is rarely just the lost relief. It is the lost relief, plus interest, plus a penalty geared to behaviour, plus the time and stress of an enquiry. And because the same fact pattern often repeats year after year, an adjustment in one year invites HMRC to look back across several. The defensible position is cheaper, calmer and entirely achievable: real work, market pay, proper records.

The evidence file that survives an enquiry

If you employ a spouse, build the file at the start, not when the enquiry letter arrives. It should contain:

  • A written employment contract setting out role, hours and pay.
  • A job description that matches what the spouse actually does.
  • A log of hours and duties, kept contemporaneously rather than reconstructed.
  • A board minute approving the appointment and the salary.
  • The market-rate benchmark, with the workings and sources you used.
  • The full RTI payroll history, payslips and submissions.
  • Bank evidence that the salary was paid into the spouse's own account.

The test of a good file is simple. Could a stranger, reading it cold, work out what the spouse did, how many hours they worked, and why the pay is reasonable for that work? If yes, you are well placed. If the file is a single payroll entry and an assertion, you are not.

How spouse employment fits the wider extraction plan

Spouse pay is one lever, not a strategy in itself. It sits alongside the small salary you take yourself, the dividends you and any shareholders draw, and the overall profit-extraction mix, including the question of how you pay yourself as a practice owner. Whether spouse pay is a company deduction or a personal-trade deduction at all depends on whether you have incorporated, which is the sole-trader-versus-limited-company decision. And once a spouse is a genuine employee, the company can also make employer pension contributions for them, opening a further tax-efficient route.

Sequence all of this inside an annual review rather than setting it once and forgetting it. As the strategic financial-planning cycle turns, profit levels move, allowances change and the 2026/27 dividend rise alters the relative attraction of each route. A spouse salary that made sense at one profit level and tax year may need resizing at the next.

Common mistakes

  • Paying the personal allowance with no work behind it. The single most common error, and the one BIM37740 is built to catch.
  • Never running payroll. A year-end journal is not a salary; no RTI trail badly weakens the case.
  • Paying into the owner's account. If the spouse never receives the money, it is not really their salary.
  • Employing a spouse with no capacity. A full-time job elsewhere plus a large practice salary for work they could not realistically do is a red flag.
  • Ignoring auto-enrolment. A genuine employee triggers genuine workplace-pension duties; skipping them creates a separate problem.
  • Reverse-engineering the salary from a tax allowance rather than from the market rate for the role.

We have seen this work cleanly in practice. A mixed NHS and private practice owner who put a spouse on the payroll at a defensible market rate, with a contract, a job description and a contemporaneous timesheet file behind it, kept the saving and never had to argue about it. The arrangements that fail are not the ones with genuine work and honest pay. They are the ones built backwards from a tax number, with nothing real underneath.

The bottom line

Employing your spouse in the dental company can genuinely cut the household tax bill where one of you is a higher-rate taxpayer and the other has unused allowances. But it earns its keep only when two things are true at once: the work is real and needed, and the pay is a market rate for that work, run through proper payroll and paid to the spouse. Build the evidence file at the outset, net off the employer NIC before you call it a saving, and review the salary each year as part of the wider extraction plan rather than fixing it and forgetting it.