# Company RegistrationNumber format

**URL:** <http://forum.companieshouse.gov.uk/t/company-registrationnumber-format/1883>\
**Category:** API Question\
**Created:** [June 27, 2018, 8:13am UTC](http://forum.companieshouse.gov.uk/t/company-registrationnumber-format/1883 "2018-06-27T08:13:22Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![bhupal\_patil](http://forum.companieshouse.gov.uk/letter_avatar_proxy/v4/letter/b/bc79bd/32.png) [@bhupal\_patil](http://forum.companieshouse.gov.uk/u/bhupal_patil)\
**Post date:** [June 27, 2018, 8:13am UTC](http://forum.companieshouse.gov.uk/t/company-registrationnumber-format/1883/1 "2018-06-27T08:13:22Z")

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Hi Team,

Do we need to supply company RegistrationNumber in specific format?

Any special characters not accepted/allowed by API?  
Any max length limit with the number?

Thanks.

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**Author:** ![MArkWilliams](http://forum.companieshouse.gov.uk/user_avatar/forum.companieshouse.gov.uk/markwilliams/32/194_2.png) [@MArkWilliams](http://forum.companieshouse.gov.uk/u/MArkWilliams)\
**Post date:** [June 27, 2018, 8:53am UTC](http://forum.companieshouse.gov.uk/t/company-registrationnumber-format/1883/2 "2018-06-27T08:53:03Z")

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Yes, full 8 characters, zero padded, any letters in uppercase.

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**Author:** ![voracityemail](http://forum.companieshouse.gov.uk/letter_avatar_proxy/v4/letter/v/b77776/32.png) [@voracityemail](http://forum.companieshouse.gov.uk/u/voracityemail)\
**Post date:** [June 27, 2018, 9:39am UTC](http://forum.companieshouse.gov.uk/t/company-registrationnumber-format/1883/3 "2018-06-27T09:39:20Z")

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As Mark says.

For the full details of what company registration numbers can be, see e.g. p.7-8 of the company URI documentation at [https://www.gov.uk/government/uploads/system/uploads/attachment\_data/file/426891/uniformResourceIdentifiersCustomerGuide.pdf](https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/426891/uniformResourceIdentifiersCustomerGuide.pdf)

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**Author:** ![frank](http://forum.companieshouse.gov.uk/letter_avatar_proxy/v4/letter/f/3d9bf3/32.png) [@frank](http://forum.companieshouse.gov.uk/u/frank)\
**Post date:** [June 27, 2018, 10:07am UTC](http://forum.companieshouse.gov.uk/t/company-registrationnumber-format/1883/4 "2018-06-27T10:07:50Z")

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The list in the published link DOES NOT INCLUDE **PC** (Protected Cell Company) or **SG** (Scottish Partnership) which were added 07/04/17 (V1.11 d). These are the latest changes I have but I have not looked for any others. There have been several updates to codes since the URI Customer Guide version on the link though these may not affect company number prefixes.