There is no single answer to what counts as a small business UK bodies will accept, because the definition changes depending on who is asking. For company accounts, Companies House uses a size test under the Companies Act 2006 with fixed limits on turnover, balance sheet total and employee numbers. For statistics and most policy, a small or medium enterprise (SME) simply means a business with fewer than 250 employees. HMRC, grant funders, lenders and public procurement frameworks then layer their own tests on top.
So the practical answer is: work out who needs the label and why, then check that body’s exact rule. A company can be legally “small” for its accounts and still fail a grant scheme’s definition, or count as an SME for a support programme while filing as a medium-sized company. This guide sets out each definition, the thresholds involved, what each band unlocks, and what happens the year you grow past a limit. Because the figures are updated periodically, treat the numbers here as a guide and confirm the current limits on gov.uk before you rely on them.
The two definitions that matter most
Almost every use of “small business” traces back to one of two systems. The first is the Companies Act size classification, which decides how you file accounts and whether you need an audit. The second is the statistical SME definition, which decides eligibility for a lot of support, grants and reporting rules.
1. The Companies Act size classification
This applies to limited companies and limited liability partnerships (LLPs). It sorts them into four bands: micro-entity, small, medium-sized and large. The band is set by a two out of three test. You measure your business against three limits, turnover, balance sheet total (the total of your assets before deducting liabilities) and average number of employees, and you qualify for a band if you do not exceed at least two of its three limits.
That “two out of three” wording matters. A property company with a large balance sheet but low turnover and few staff can still be small, because it only breaches one limit. The thresholds below apply to financial years beginning on or after 6 April 2025. Earlier years use lower figures, so if you are finalising older accounts, check the version that applied then.
| Size band | Employees (max) | Turnover (max) | Balance sheet total (max) | What the band unlocks |
|---|---|---|---|---|
| Micro-entity | 10 | £1m | £500,000 | Very short accounts, minimal public disclosure, usually no audit |
| Small | 50 | £15m | £7.5m | Simpler accounts, usually audit-exempt, less detail on the public record |
| Medium-sized | 250 | £54m | £27m | Fuller accounts, audit normally required, more disclosure |
| Large | Over 250 | Over £54m | Over £27m | Full statutory accounts and audit, most disclosure |
Confirm the live figures on the gov.uk pages for micro-entities, small and dormant companies and for audit exemptions for private limited companies, as thresholds and rules do change.
2. The statistical and policy SME definition
Government statistics, the Department for Business and Trade, and many support schemes use a simpler headcount rule that treats “SME” as anything with fewer than 250 employees. It splits into three tiers:
- Micro: 0 to 9 employees
- Small: 10 to 49 employees
- Medium: 50 to 249 employees
Some versions of this definition, particularly those inherited from EU rules, also apply turnover and balance sheet ceilings alongside the headcount. If a grant or programme quotes an SME definition, read its small print, because the financial ceilings and how they treat linked companies vary from scheme to scheme.
Why the classification genuinely matters
This is not a labelling exercise. Your size band changes your costs, your workload and how much of your finances the public can see.
Audit exemption
Most small and micro companies can skip a statutory audit, which typically saves several thousand pounds a year and weeks of preparation. You lose that exemption if you grow into the medium or large bands, or if shareholders holding at least 10 percent demand an audit, or if your articles or a lender require one. An audit is not a bad thing, but it is a real cost you should plan for before you cross the line.
How much ends up on the public record
Anyone can view your accounts at Companies House for free. Smaller companies can file less, which keeps commercially sensitive detail out of public view. Your filing options are:
| Filing option | What you disclose | On the public record | Best for |
|---|---|---|---|
| Micro-entity accounts | A very simple balance sheet with limited notes | The least detail | The smallest companies wanting minimal disclosure |
| Small (filleted) accounts | Balance sheet and limited notes, profit and loss often omitted | Little detail on trading | Small companies keeping margins private |
| Full accounts | Full statements including profit and loss and directors’ report | The most detail | Companies needing to show full performance, or those required to |
Note that recent Companies House reforms are tightening what small and micro companies can leave out, so the ability to file heavily reduced accounts is narrowing. This sits alongside other changes such as mandatory Companies House identity verification for directors, which every director now needs to complete.
Reliefs, schemes and employment rules
Size can affect eligibility for certain tax reliefs, research and development schemes, and grant funding. It can also change which reporting duties apply, for example payment practices reporting, which targets larger businesses. A number of employment law obligations scale with headcount too, so knowing your true employee count is worth the effort. If you are moving from working alone to taking someone on, our checklist for hiring your first employee in the UK walks through PAYE, pensions and insurance in the right order.
What happens when you cross a threshold
Growing companies get caught out here more than anywhere else, so it pays to understand the mechanics.
The two consecutive years rule
You do not change size band the moment you exceed a limit once. Under the Companies Act, your classification generally only changes if you exceed (or fall below) the thresholds for two consecutive financial years. So a single bumper year that pushes you over the small-company turnover limit does not automatically strip your exemptions. If you exceed the limits again the next year, the change usually takes effect for that second year.
There is a first-year nuance for brand new companies: in your very first financial year, you are assessed on that year alone, so a fast start can put a startup straight into a larger band. The transition also works both ways, meaning a shrinking company must usually be below the limits for two years running before it can claim smaller-company treatment again.
Why growing firms trip up
The common mistake is discovering the change too late. Owners plan for a busy year, breach a limit twice without noticing, and only learn at accounts time that they now need an audit and fuller disclosure, with no budget set aside. The fix is to check your position against all three tests at each year end while you still have time to prepare. A rolling view of the numbers helps, and our guide to cash flow forecasting with the 13-week method keeps the financial picture in front of you rather than arriving as a surprise.
How HMRC, lenders and grant bodies differ
Your Companies House size band is not the last word. Several other bodies run their own tests.
HMRC cares about specific thresholds rather than a single “small” label. VAT registration is triggered by taxable turnover, currently around £90,000 (approximate and subject to change), regardless of your accounts size band. Making Tax Digital for Income Tax phases in by income level for sole traders and landlords, which our SME guide to Making Tax Digital explains in detail. Reliefs and schemes each define eligibility in their own way.
Lenders apply their own affordability and size criteria, and public-backed finance often uses the fewer-than-250-employees SME test. Support from bodies such as the British Business Bank flows through partners to smaller firms, as seen when the British Business Bank backed Social Investment Scotland.
Grant funders and procurement frameworks frequently use the statistical SME definition, sometimes with extra rules on ownership. This is why a business can be small for its accounts yet fail a grant test, or qualify for an SME programme while filing as a medium-sized company. Always read the specific eligibility criteria for the money or contract in front of you.
Mistakes people actually make
- Assuming one definition covers everything. The label that decides your audit is not the label that decides a grant. Check each one separately.
- Testing turnover only. The Companies Act test uses turnover, balance sheet total and employees together, on a two out of three basis. A big balance sheet alone can push you up even with modest sales.
- Forgetting the two-year rule works both ways. Owners assume they drop back to small treatment the moment revenue falls, but you usually need two consecutive years below the limits.
- Ignoring group companies. If you sit in a group, size is often assessed across the whole group, not just your one entity, which catches out founders who set up several small companies.
- Filing the wrong reduced accounts. Reforms are limiting how much small and micro companies can leave out. Filing an out-of-date reduced format can mean rejected or non-compliant accounts.
- Not budgeting for the jump. Crossing into the medium band brings audit and disclosure costs. Plan for them before the year in which they bite.
Frequently asked questions
Do sole traders count as small businesses?
Yes, in everyday and statistical terms a sole trader with fewer than 10 or 50 staff is a micro or small business. However, the Companies Act size classification only applies to companies and LLPs, so sole traders and ordinary partnerships do not file accounts at Companies House or fall into those bands. Their obligations run through Self Assessment and, increasingly, Making Tax Digital.
How are group companies treated?
Where a company is part of a group, its size is usually assessed on the group as a whole, combining turnover, balance sheet totals and employees across the members. This stops a larger operation splitting itself into several nominally small entities to keep exemptions. If you run more than one company, get the group position checked rather than assuming each entity is judged alone.
Does a part-time employee count as one person?
For the Companies Act test, the figure is the average number of employees during the year, calculated month by month, and it counts people employed under contracts of service rather than full-time equivalents. In practice each employee on the payroll counts as one for that measure, though schemes with their own definitions may convert to full-time equivalents. Check the exact method the relevant body uses before relying on your headcount.
What happens the year I grow past a limit?
A single year over a threshold usually does not change your band, because most changes need two consecutive years outside the limits. If you exceed the limits again the following year, your new classification generally applies from that second year, which may mean an audit and fuller accounts. Established companies get the two-year cushion; a company in its first financial year is judged on that year alone.
Where do I confirm the current thresholds?
Use the gov.uk guidance on company accounts and audit exemptions, and Companies House guidance for filing formats, as these hold the live figures. The numbers are reviewed periodically, so a printed figure can go out of date. If real money rides on the answer, confirm it with your accountant against the year in question.
What to do next
- Identify who is asking and why. Write down each place the “small business” label matters to you right now, such as your accounts, a specific grant, a lender or a procurement bid, and note the definition each one uses.
- Run the two out of three test at your year end. Measure turnover, balance sheet total and average employees against the current bands, and if you are in a group, do it across the group. Confirm the figures on the gov.uk company accounts guidance.
- Plan for any threshold you are close to. If two years above a limit looks likely, budget for the audit and disclosure that follow, and speak to your accountant before the second year closes rather than after.
- Keep your Companies House record clean. Check your SIC code is still accurate, complete director identity verification, and file the correct account format for your size, since the rules on reduced accounts are tightening.
