A company registration number is an identifier assigned to a legal entity by the authority that registers it. It is designed to distinguish that entity inside a defined register. The number is generally more stable than the company name, address, directors or trading brand, which makes it a critical input for company search, verification and data matching.
The definition sounds simple, but the phrase is used loosely. In one country it may clearly mean the number issued by a national companies register. In another, particularly the United States, it may refer to a state entity number, an EIN, a tax account or even a local business licence. Those identifiers are not interchangeable.
A usable registration identifier therefore needs context. At minimum, record:
- the identifier value exactly as issued;
- the country and, where relevant, state or province;
- the issuing registry or authority;
- the identifier type, such as company number, entity ID or file number;
- the legal entity to which it belongs;
- the source and date on which it was verified.
The same digits can exist in several identifier systems. Treating a bare number as globally unique can connect a customer, supplier or payment record to the wrong company. CompanyDelta’s entity resolution guide explains how scoped identifiers should be combined with legal names, addresses and supporting evidence.
A company registration number is not just a string. Its identity is the combination of value, identifier type and issuing jurisdiction. Keep all three together.
A registration number becomes reliable when its scope is known
Identity modelThe value alone is incomplete. Scope prevents the same-looking number from being interpreted as a different registry, tax or licence identifier.
Company registration number, tax number, VAT number and LEI are different
Businesses accumulate identifiers because authorities and market infrastructures serve different purposes. One number establishes the record in a company register; another administers tax; another identifies a VAT account; another supports financial-market reporting. A company can legitimately have several.
- Company registration number
- Identifies a legal entity inside the register maintained by the incorporating or registering authority.
- Tax identifier
- Identifies a taxpayer or tax account. In the United States, the federal EIN is a tax identifier and is not the state company file number.
- VAT or GST number
- Identifies a business registration for an indirect-tax regime. A group or branch treatment may differ from the underlying company register.
- Legal Entity Identifier
- A globally standardised identifier used in financial transactions and reporting for eligible legal entities. It supplements rather than replaces the local registry number.
- Business licence number
- Shows an authorisation to conduct a particular activity or operate in a location. It is not necessarily the legal entity’s formation identifier.
Some systems embed or reuse another identifier. That does not make the concepts identical. An Australian company has an Australian Company Number and can also have an Australian Business Number. The values are related for companies, but their issuing systems and uses remain different.
When a form asks for a “business registration number”, determine what the receiving organisation means before submitting a value. Record the field label, help text and target country. A valid number of the wrong type can pass a format check and still identify the wrong account.
One business can have several identifier layers
Identifier mapIdentifiers should be linked to one resolved entity without being collapsed into one generic “registration number” field.
How company identifiers differ by country
There is no universal company-number format. Even where a country has a central register, prefixes can distinguish entity types or jurisdictions. Federated countries may have both national and state or provincial identifiers.
| Jurisdiction | Company identifier | Important distinction |
|---|---|---|
| United Kingdom | Companies House company number, eight characters including any prefix or leading zeros | It is not the UTR, VAT number or Companies House authentication code |
| United States | State-issued entity, file, charter or control number | The format and authority vary by state; the federal EIN is a separate tax identifier |
| Australia | Australian Company Number, a unique nine-digit company identifier | The Australian Business Number has a broader business and tax-administration role |
| Singapore | Unique Entity Number for registered entities | It is used across government interactions and can cover entity types beyond companies |
| Canada | Corporate identifiers can be federal or provincial; the CRA Business Number is a unique nine-digit business identifier | Record the incorporating registry separately from tax programme account identifiers |
These examples show why software should not apply a single length or digit-only rule globally. Validation belongs to a country-and-identifier catalogue. CompanyDelta’s data dictionary separates company identifiers from tax, financial and relationship fields, while the coverage view shows which company and linkage records are available by country.
Entity type also matters. Sole traders, partnerships, branches, charities and public bodies may be registered in different systems or may not receive the same company number as an incorporated company. “No company number” can be a legitimate result for one entity type, but it should never be assumed from a failed search.
How to find a company registration number
The most reliable route is the official register for the company’s jurisdiction. Start by identifying the legal entity and its place of incorporation, not the brand or website alone.
Confirm the country and legal name
Use contracts, invoices or onboarding documents to identify the proposed legal party. Keep trading names separately and note whether the record refers to a parent, branch or subsidiary.
Choose the correct official register
Use the national registrar where one exists. For US companies, select the Secretary of State or equivalent authority in the formation state. Do not assume the operating address identifies the formation state.
Search with several known facts
Search the exact and normalised legal name, then compare address, status, formation date and officers. A name result is a candidate until supporting facts agree.
Copy the complete identifier
Preserve leading zeros, letters, prefixes and separators as issued. Spreadsheet conversion can silently remove leading zeros or turn long numbers into scientific notation.
Capture the source record
Store the registry name, source link or reference, retrieval time and key matching facts. A bare number copied from a website is not equivalent to a verified registry result.
For your own company, the number may appear on the certificate of incorporation, registry extract, annual filings or official correspondence. It can also appear on invoices and websites where local disclosure rules require it. Verify it against the registry before using it as a master-data key.
Do not ask a supplier for “the registration number” without specifying country and number type. A structured request—legal name, formation country, issuing registry and company number—reduces ambiguity and gives the reviewer enough information to reproduce the match.
From business name to verified registry number
Search workflowFinding a candidate number is not the end of the search. The legal-party match and source evidence determine whether it can be trusted.
How to verify a company registration number
Format validation is useful, but it only tells you that a value could belong to an identifier system. Verification confirms that the issuing authority returns the expected legal entity.
1. Validate the number without changing it
Check allowed length, characters, prefix and checksum where the identifier standard provides one. Do not strip leading zeros or letters to make a value fit. Normalise a separate comparison field while preserving the original.
2. Query the authoritative source
Search the official register or retrieve the registry record through a trusted source. Record whether the lookup succeeded, returned no match, was unavailable or required access that was not available. Those outcomes are different.
3. Compare the legal entity
Check legal name, jurisdiction, entity type, registered address and current status. A correct-format number attached to a different company is a failed verification, not a partial match.
4. Resolve apparent conflicts
A former name or historical address may explain a difference. A merger, conversion or re-registration can create a successor entity with a different identifier. Review effective dates before deciding that one source is wrong.
5. State the evidence level
Use clear outcomes such as verified against official register, supported by company document, format valid but unverified, conflicting or no match. Avoid a single green check that hides the source and date.
The broader KYB verification process builds on this result by assessing status, ownership, control, screening and decision rules. A verified number proves the identifier-to-entity link; it does not establish that the company is low risk.
Format checks and registry verification answer different questions
Verification matrixA number can pass a format rule and still belong to another company. Authoritative registry evidence is what connects it to the legal entity.
How registration numbers improve business workflows
A verified registration number can act as the anchor between systems. The same legal entity may appear as a supplier, customer, counterparty and portfolio company. A stable, scoped identifier helps teams connect those records without merging separate subsidiaries.
Supplier and customer onboarding
Capture country and registry number early. Use them to retrieve the legal name and status, then compare those values with the contract and payment beneficiary. Preserve any unresolved difference rather than silently replacing the submitted value.
Screening and ownership
Sanctions, adverse information and ownership results depend on the subject being resolved correctly. The registration number helps distinguish namesakes and provides the starting node for tracing shareholders and corporate parents.
CRM and vendor-master quality
Use one stable internal company ID linked to the external registry identifier. Customer, supplier and account records can retain their own workflow fields while pointing to the same legal entity. The number should not overwrite the internal account ID.
Ongoing monitoring
Monitor the resolved entity, not a name string. Names and addresses can change while the registry identity continues. Reopen the match when a source indicates a merger, conversion, branch closure or other event that may create a new legal entity.
The CompanyDelta API supports structured company retrieval, while source and evidence guidance explains how to retain provenance for review.
Store company identifiers as repeatable evidence
A single “registration number” text field is not enough for global data. Use a repeatable identifier object so one entity can hold the identifiers relevant to its jurisdictions and purposes.
For each identifier, store:
- raw value and normalised comparison value;
- identifier scheme and human-readable type;
- country and subnational jurisdiction where applicable;
- issuing authority or registry;
- validity or verification status;
- source reference and retrieval timestamp;
- effective dates where the source supplies them;
- the resolved internal company ID.
Do not delete a historical identifier simply because the company has changed structure. Mark the relationship and dates, then link any successor entity separately. Keep tax accounts and licences in their own schemes rather than promoting whichever number arrived first into the master key.
A durable identifier record keeps value, scope and evidence together
Data modelOne company can have several valid identifiers. A structured model preserves their meaning while keeping them connected to one resolved entity.
Company registration number questions answered
What is a company registration number?
It is an identifier assigned to a legal entity by the authority that registers it. Its meaning depends on the identifier type and issuing jurisdiction.
How do I find a company registration number?
Confirm the legal name and incorporation jurisdiction, search the relevant official company register, compare the returned details and copy the complete identifier with its prefix or leading zeros.
Where can I find my company registration number?
It may appear on the certificate of incorporation, registry extract, official filings or registrar correspondence. Verify it against the official register before using it as a master identifier.
Is a company registration number the same as an EIN?
No. In the United States, an EIN is a federal tax identifier. Companies and LLCs are generally registered at state level and receive a separate state entity or file number.
Is a company registration number the same as a VAT number?
No. A company number identifies the legal entity in a company register, while a VAT number identifies a registration in an indirect-tax system.
Do US companies have a company registration number?
US entities usually receive a number from the state where they form or register, but naming and formats vary. There is no single nationwide company-registration number equivalent to the UK company number.
Do sole traders have a company registration number?
Not necessarily. A sole trader may have tax, business-name or licence identifiers without being an incorporated company. The answer depends on the jurisdiction and registration system.
Does a company registration number change?
It often remains stable while names, addresses and officers change. A new legal entity created through restructuring, conversion or re-incorporation may receive a different number.
Can I verify a company using only its registration number?
The number is a strong search key, but verification should confirm that the official registry record matches the expected legal name, jurisdiction and entity type.
Why must the country be stored with the registration number?
Because number formats and issuing systems are jurisdiction-specific. The same-looking value can exist in different registers or identifier schemes.
Resolve the company before relying on the number.
Connect registry identifiers to legal entities, source evidence and the workflows that use them.