# UK Companies House Number Check

> Validate a UK Companies House company number format (eight characters) before you query the register.

Canonical: https://corpoapi.com/country-search/companies-house-search

Type an eight-character Companies House number and get an instant format verdict: plain digits or a known two-letter series plus six digits, with leading zeros preserved.

## Worked examples

### A plain eight-digit number

Input: `00445790`

- **Company number**: 00445790

- **Format**: Eight digits

- **Leading zeros**: Kept

- **Verdict**: Well formed

The check judges the format alone. Use UK company search or a profile call to confirm the company behind the number.

### A Scottish registration in the SC series

Input: `SC117120`

- **Company number**: SC117120

- **Format**: Two letters, SC series, plus six digits

- **Verdict**: Well formed

SC is the series Companies House uses for Scottish registrations.

### Seven digits, so the shape is wrong

Input: `4457900`

- **Digits**: 7

- **Needed**: 8

- **Verdict**: Not a UK company number

The leading zero is part of the number, so dropping it leaves the wrong length.

## FAQ

### Does this search Companies House?

No. It checks the format of the number in your browser. To search the register, use UK company search on this site or pass the number to GET /v1/companies/gb/{company_number} after you have a key.

### Does a valid number prove the company exists?

No. A valid format only means the number is well formed. It does not prove the number was issued or that the company is still trading.

### Why does 4457900 not work?

A UK company number is eight characters wide, so the leading zeros count. 00445790 is a valid shape and 4457900 is not.

### What are the two-letter prefixes?

SC is Scotland, NI is Northern Ireland, OC is a limited liability partnership, and other series cover society, overseas and similar registers.

### Is the check free?

Yes. No account is needed. The format rule runs in your browser first, so a typo is free to correct, and a well-formed company number uses one of the tool's 5 daily checks.

### Is a company number the same as a VAT number?

No. A company number identifies the legal entity in the register that issued it. A VAT number is issued by a tax authority and has its own check on this site.