uk-company-number

Validate, format, and identify UK Companies House company numbers. Zero dependencies.

Built by BORSCH.AI — UK Business Intelligence Platform covering 5.9M companies with AI-powered risk analysis and 50M+ government data signals.

Features

• Validate UK company numbers (format check)
• Parse into structured info (jurisdiction, type, prefix)
• Format/normalize to canonical form
• Support for all 27 known prefixes (England & Wales, Scotland, NI, LLP, LP, overseas, etc.)
• Compare two numbers for equality
• Zero dependencies
• TypeScript types included
• ESM and CommonJS support

Installation

npm install uk-company-number

Quick Start

import { validate, parse, format } from "uk-company-number";

// Validate
validate("12345678");   // true (England & Wales)
validate("SC123456");   // true (Scotland)
validate("OC301234");   // true (LLP)
validate("XX000000");   // false (unknown prefix)

// Parse
parse("SC123456");
// {
//   number: "SC123456",
//   prefix: "SC",
//   numericPart: "123456",
//   jurisdiction: "scotland",
//   jurisdictionName: "Scotland",
//   type: "ltd",
//   typeName: "Private Limited Company"
// }

// Format (normalize)
format("123");          // "00000123"
format("sc 123456");    // "SC123456"

API

validate(number: string): boolean

Check if a string is a valid UK company number format.

validate("12345678");    // true
validate("SC123456");    // true
validate("OC301234");    // true
validate("OE012345");    // true (Overseas Entity)
validate("00000000");    // false (all zeros)
validate("XX123456");    // false (unknown prefix)

parse(number: string): CompanyNumberInfo | null

Parse a company number into structured information.

const info = parse("OC301234");
// {
//   number: "OC301234",
//   prefix: "OC",
//   numericPart: "301234",
//   jurisdiction: "england-wales",
//   jurisdictionName: "England & Wales",
//   type: "llp",
//   typeName: "Limited Liability Partnership"
// }

format(number: string): string | null

Normalize a company number to its canonical form.

format("123");           // "00000123"
format("sc123456");      // "SC123456"
format("OC 301234");     // "OC301234"
format("12.345.678");    // "12345678"

getJurisdiction(number: string): string | null

Get the jurisdiction identifier.

getJurisdiction("12345678");  // "england-wales"
getJurisdiction("SC123456");  // "scotland"
getJurisdiction("NI012345");  // "northern-ireland"
getJurisdiction("SE123456");  // "uk"

getType(number: string): string | null

Get the company type identifier.

getType("12345678");  // "ltd"
getType("OC301234");  // "llp"
getType("LP123456");  // "lp"
getType("FC123456");  // "overseas"
getType("SE123456");  // "se"
getType("CE123456");  // "community-interest"

getPrefix(number: string): string | null

Get the letter prefix (empty string for England & Wales).

getPrefix("12345678");  // ""
getPrefix("SC123456");  // "SC"
getPrefix("OC301234");  // "OC"

equals(a: string, b: string): boolean

Check if two numbers refer to the same company.

equals("123", "00000123");       // true
equals("sc123456", "SC123456");  // true
equals("SC123456", "NI123456");  // false

prefixes(): PrefixInfo[]

Get all known prefixes and their descriptions.

prefixes();
// [
//   { prefix: "AC", jurisdiction: "england-wales", type: "assurance", ... },
//   { prefix: "CE", jurisdiction: "england-wales", type: "community-interest", ... },
//   ...
// ]

Supported Prefixes

| Prefix | Jurisdiction | Type | Description | |--------|-------------|------|-------------| | (none) | England & Wales | ltd | Private Limited Company | | SC | Scotland | ltd | Private Limited Company | | NI | Northern Ireland | ltd | Private Limited Company | | R | England & Wales | ltd | Old Public Company (pre-1981) | | OC | England & Wales | llp | Limited Liability Partnership | | SO | Scotland | llp | Limited Liability Partnership | | NC | Northern Ireland | llp | Limited Liability Partnership | | FC | United Kingdom | overseas | Overseas Company | | SF | Scotland | overseas | Overseas Company | | NF | Northern Ireland | overseas | Overseas Company | | OE | United Kingdom | overseas | Overseas Entity | | LP | England & Wales | lp | Limited Partnership | | SL | Scotland | lp | Limited Partnership | | NL | Northern Ireland | lp | Limited Partnership | | IP | England & Wales | industrial-provident | Industrial & Provident Society | | SP | Scotland | industrial-provident | Industrial & Provident Society | | NP | Northern Ireland | industrial-provident | Industrial & Provident Society | | RC | England & Wales | royal-charter | Royal Charter Company | | SR | Scotland | royal-charter | Royal Charter Company | | NR | Northern Ireland | royal-charter | Royal Charter Company | | SE | United Kingdom | se | Societas Europaea | | GE | United Kingdom | eeig | European Economic Interest Grouping | | CE | England & Wales | community-interest | Community Interest Company | | CS | Scotland | community-interest | Community Interest Company | | AC | England & Wales | assurance | Assurance Company | | SA | Scotland | assurance | Assurance Company | | NA | Northern Ireland | assurance | Assurance Company |

Data Source

Based on the official Companies House company number format specifications.

Need More Company Data?

This package validates company number formats. To look up full company details — financials, directors, risk scores, government signals, and AI-powered analysis across 5.9 million UK companies — visit borsch.ai.

License

MIT