UK Postcodes – which postcode result should you use & when?

There are a couple of Kleber methods that provide postcodes for the UK. When retrieving the results in these methods you will note that there are what look like two postcodes listed.

In both methods you should always use the postcode listed at the Output Field 'Postcode' when you need to display or write out the address on mail, letters, websites, labels, etc. This is the postcode that the general public know as their own.

E.g. ‘38 Mill Hill, Haverhill, Suffolk’ has a postcode of ‘CB9 8BU’.

The other postcode that can be found in the results is longer and is used for creating a barcode for bulk mailing purposes. This postcode contains an extra 2 or 3 characters that should NOT to be divulged to the public – ie, not written into addresses or shown on labels etc. The first two extra characters are the Delivery Point Suffix (DPS*) and the third (if included) is a checksum** character to ensure there are no errors in the barcode.

E.g ‘38 Mill Hill Haverhill Suffolk’ has a postcode for creating a barcode of ‘CB9 8BU1U’ or ‘CB9 8BU1UZ’. The ‘1U’ component is the DPS and the ‘Z’ at the end is the checksum component.

Please ensure you use the postcode found in the Output field called 'Postcode' when writing or displaying the actual UK address. Only use the other when creating a barcode.


Specific method information

Currently Kleber uses the following methods when you are either retrieving/verifying a UK address:

  1. Capture.Address.Predictive.UkPaf.RetrieveAddress method
    This method will return an output field called ‘Postcode’ for addressing purposes and one called ‘Barcode’ for barcoding purposes. The barcode result includes both the DPS and checksum components.

E.g. ‘38 Mill Hill Haverhill Suffolk’ returns ‘CB9 8BU’ at Postcode and ‘(CB9 8BU1UZ)’ at Barcode.

  1. Verify.Address.IntGdc.VerifyAddress method
    This method is an international one – but when used for UK addresses will return two postcodes. The one used for addressing is found in the 'PostCode' output field. The one found in the 'AddressLine' output field further up the list contains the postcode with the DPS on the end. This should never be used when displaying the address.

E.g. ‘38 Mill Hill Haverhill Suffolk’ returns ‘CB9 8BU’ at Postcode and ‘CB9 8BU1U’ at AddressLine4.


* DPS – the Delivery Point Suffix is a code made up of one numeric + one alpha component e.g 9A. It is used to uniquely identify each property within each unit postcode and to facilitate fully automatic sorting of bulk barcoded mail by Royal Mail.    

** Checksum - The checksum character is used as a means of error detection to ensure that the rest of the barcode is correct

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