A SIC (Standard Industrial Classification) code is a 5-digit code describing what your UK company actually does, used on the Companies House register. You pick 1-4 codes at incorporation. The current edition is UK SIC 2007, which is being replaced by UK SIC 2026.
Getting the SIC code wrong won''t stop you incorporating, but it can cause friction later — particularly with banks, insurers, and lenders that match risk profile to SIC code.
Why SIC codes matter
- Government statistics: SIC codes feed ONS economic data — what UK businesses do and how each sector is growing.
- Banking and insurance underwriting: many banks decline accounts (or charge higher fees) for SIC codes in restricted sectors — crypto, adult content, gambling, certain financial activities. Insurers price premiums against SIC code, so a misclassified company can be paying too much (or have invalid cover).
- Public perception: your SIC code appears on Companies House, on credit reports (Experian, Dun & Bradstreet, Creditsafe), and in B2B data feeds. A wrong code can mean prospects'' procurement teams flag the company unnecessarily.
- R&D tax relief: HMRC uses SIC codes (alongside other factors) to assess the credibility of R&D claims. A software company classified as "Wholesale of motor vehicles" raises questions.
How to find the right code
- Use the Companies House SIC code lookup and search by keyword.
- Read the description, not just the code title — the official text drives interpretation.
- Pick the code that most precisely matches your primary activity. If you do multiple things, you can list up to 4 codes.
Common examples for UK SMEs:
| Activity | SIC code |
|---|---|
| Software development (general) | 62012 |
| Software publishing (off-the-shelf) | 58210 |
| Web portals | 63120 |
| Accountants and bookkeepers | 69201 |
| Solicitors | 69101 |
| Estate agents | 68310 |
| Letting agents | 68320 |
| Holiday letting | 55209 |
| Management consultancy | 70229 |
| Marketing consultancy | 73110 |
| Online retail (mail order) | 47910 |
| Construction (general) | 41200 |
| Restaurant | 56101 |
| Generic catch-all | 82990 (Other business support service activities) |
If your activity is genuinely novel — there''s no SIC code that fits — use 82990. It''s not ideal but it''s honest. The alternative — picking a more-specific code that''s wrong — causes more problems.
What about multiple activities?
You can list up to 4 SIC codes. List them in order of importance — the first is your primary activity. Many SMEs only need one. Use multiple if you genuinely run separate activities, but don''t pad — five marginal activities listed dilutes the picture.
When and how to change a SIC code
If your activities have changed materially, update the codes on your next confirmation statement (or sooner, via a standalone CS01). It''s free.
The trigger is "material change in activity" — a one-off project outside your normal trade doesn''t require an update.
The move to UK SIC 2026
A new edition (UK SIC 2026) is being introduced to align with the international ISIC Rev. 5 update. The headline changes:
- Better coverage of digital and platform economy activities.
- More granular technology, AI, and information services categories.
- Updated environmental and circular economy activities.
- Some old codes split, others merged.
The transition is being phased. Companies House will eventually re-issue codes to match the new edition, but for now (May 2026) UK SIC 2007 remains the operative version. Watch the ONS announcements for the implementation date.
What to do next
- If you''re incorporating: pick the most precise SIC code that fits, using the Companies House lookup. Don''t default to 82990 unless nothing else fits.
- If you incorporated some time ago: pull up your record on Companies House and re-read your SIC codes. If your business has pivoted, update on the next confirmation statement.
- If you''re being declined by banks or insurers: check whether your SIC code is contributing. Updating may not solve underlying concerns but it removes the surface-level cause.