What Are SIC Codes?
The Standard Industrial Classification (SIC) system is used by Companies House, HMRC, and the Office for National Statistics (ONS) to categorise businesses by their economic activity. Every UK company must provide at least one SIC code when registering, and can list up to four codes to describe their activities. The system ensures consistency across government departments, enables economic analysis, and determines certain regulatory requirements.
SIC 2007 Structure
The current system (UK SIC 2007) is based on the EU classification system NACE Rev. 2 and contains 731 five-digit codes organised into a hierarchy: 21 sections (A-U), 88 divisions (2-digit), 272 groups (3-digit), 615 classes (4-digit), and 731 subclasses (5-digit). Each level adds specificity — for example, Section J (Information and Communication) → Division 62 (Computer programming and consultancy) → Group 620 → Class 6202 → Subclass 62020 (Information technology consultancy activities).
The 21 sections cover the full range of economic activity, from Section A (Agriculture, Forestry and Fishing) through to Section U (Activities of Extraterritorial Organisations). The most commonly used codes include 70229 (Management consultancy), 62020 (IT consultancy), 68100 (Buying/selling real estate), 47910 (Retail via mail order/internet), and 99999 (Dormant company — no trading activity).
How to Choose the Right SIC Code
Choosing the correct SIC code matters because it determines how a company is classified in official statistics, affects its filing requirements with HMRC, and can influence the regulatory framework that applies to its operations. HMRC uses SIC codes to identify industries for compliance checks, and insurers may use them to assess risk categories.
Companies should choose the code that most closely matches their primary revenue-generating activity. If a company operates across multiple sectors, it can list up to four SIC codes in order of significance. The primary SIC code (SIC code 1) carries the most weight for statistical classification.
SIC Code Updates and Changes
Companies can change their SIC codes at any time by filing an update with Companies House, typically done via the confirmation statement. A planned revision (SIC 2025, based on ISIC Rev. 5) is expected to update the classification to better reflect the modern economy, including better coverage of digital services, gig economy platforms, and green energy sectors.
SIC Codes on UVAGATRON
UVAGATRON tracks SIC codes for all 16.6 million UK registered companies (active and dissolved), enabling industry-level analysis, benchmarking, and competitor identification across 731 industry categories. Our SIC Code Directory at /sic-codes provides browsable access to all codes with live company counts, top locations, and industry trends.