Royal Mail Mailmark™ Barcode FAQ

Barcode Information | Tutorials | Examples

Royal Mail Mailmark™ barcodes was developed for machine readable Business Mail in Letter and Large Letter formats. Mailmark is replacing the Customer Barcode or CBC January 2018. The Mailmark barcodes include additional information that the CBC and Delivery Point Suffixes (DPS) was not able to include, such as tracking mail and delivery status, predictions of when mail will be delivered for marketing and advertising purposes and reporting statistics with data analysis.

Royal Mail Mailmark

Mailmark™ barcodes are either 4-State or 2 Dimensional (2D) Complex Mail Data Mark (CMDM) barcodes. The amount of data needed to be encoded in the barcode will dictate which version needed to be used. You must be registered to receive barcode savings:


2 Dimensional (2D) Complex Mail Data Mark (CMDM)

There are three types of Complex Mail Data Mark barcodes that are ECC200 Data Matrix type formats using the ISO/IEC 16022 specifications:

  • Type 7:
    • Letters
    • Barcode Size: 24 x 24 modules
    • Physical Size: 12 x 12 mm
    • Total Character Count: 51 Characters
    • Customer Use: 6 spare spaces
  • Type 9:
    • Large Letters, including polywrap
    • Barcode Size: 32 x 32 modules
    • Physical Size: 16 x 16 mm
    • Total Character Count: 90 Characters
    • Customer Use: >25 but max of 45 spare spaces
  • Type 29:
    • Large Letters, including polywrap letters.
    • Barcode Size: 16 x 48 modules
    • Physical Size: 8 x 24 mm
    • Total Character Count: 70 Characters
    • Total Character Count: need 6-25 customer characters

The encodation scheme required for MailMark is C40, character subset 0, which is the basic set that encoders only upper case characters, numbers and the space character.

 DescriptionStart PositionChar LengthDefinitionData ValuesType 7
Example Values
Type 9
Example Values
Type 29
Example Values
UPU Country ID14Identifies the UPU Country IDJCB<space>JCB<space>JCB<space>JCB<space>
Information Type ID51Identifies the
Royal Mail
barcode payload
for each product
0 – Domestic Sorted & Unsorted
1 – International Sorted & Unsorted (for potential future use)
2 – Response Services (for potential future use)
A – Online Postage
B – Franking
C – Consolidation
Version ID61Identifies the
barcode version
as relevant to
each Information
Type ID.
Currently “1” – For Mailmark™ barcode111
Format1Identifies the
format of the item.
0 – Null or Test
1 – Letter
2 – Large Letter
3 – Packet (for potential future use)
4 – Parcel (for potential future use)
5 to 9 – Spare (for potential future use)
A to Z – Spare (for potential future use)
Class71Identifies the
class of the item.
0 – Null or Test
1 – 1C (Retail)
2 – 2C (Retail)
3 – 3C (Retail)
4 – Premium (Retail Publishing Mail) (for potential future use)
5 – Deferred (Retail)
6 – Air (Retail) (for potential future use)
7 – Surface (Retail) (for potential future use)
8 – Premium (Network Access)
9 – Standard (Network Access)
A to Z – Spare (for potential future use)
Supply Chain ID87Identifies the
unique chain of
involved in the
0000000 to 9999999123456712345671234567
Item ID158Identifies the
unique item within
the Supply Chain
00000000 to 99999999123456781234567812345678
Destination Post Code plus DPS239Contains the Postcode of the
Delivery Address
with DPSIf inland the
contains the
following number
of characters. Area (1 or 2
District (1 or 2
Unit (2
DPS (2
The PC and DP must comply with a valid PAF format (see appendix A).

If there was no DP and a Unit is present then a default 9Z DP shall be used.

If no Unit information is available the Sector Unit and Delivery Point fields will not be included. e.g.

If International (potential future use only) , then “XY11” shall be used as the Outward element with no Inward or DP as follows:

If no destination post code information is available this field shall be filled with 9 <space> characters.

RTS Flag321Flag which
indicates what
level of RTS
service is being
“0” – None

“1” – Response Services Unique (for potential future use)

Return to Sender Post Code337Contains the
Return to Sender
Post Code but no
The PC (without DPS) must comply with a PAF® format (see Appendix A). If no RTS post code exists this field shall be filled with 7 <space> characters.<space><space>
Reserved406Reserved by Royal MailMust be filled with <space> characters until further notice.<space><space>
Customer Content46Optional space for
use by customer.
Any data as required by the customer up to the maximum size for that format of barcode. Unused spaces must be left blank to maximize error correction capability.6 Characters for customers45 Characters for customers25 Characters for customers
Total Character CountThis is the maximum
practical capacity of the format
52 Total Char90 Char70 Char

Mailmark 4-state Barcode

There are two types of 4 State barcodes on printed postage 1st class and 2nd class with English and Bilingual Welsh / English options.

  • Barcode L, which is a Long barcode for domestic sorted and unsorted customers.
    • Number of Bars: 78
    • Physical Size: Approximately 89 mm (at 21.2 bars per inch)
    • Content: 26 Characters
  • Barcode C, which is a domestic sorted Consolidator customer.
    • Number of Bars: 66
    • Physical Size: Approximately 76.2 mm (at 21.2 bars per inch)
    • Content: 22 Characters
 Field NameCharacter LengthDefinition & CommentsData ValuesBarcode C
Example Values
Barcode L
Example Values
Format1Identifies the format of the item.
Used in place of Information Type ID for Barcode C and L.
0 – Null or Test
1 – Letter
2 – Large Letter
Version ID1Identifies the barcode version1 – Mailmark Barcode11
Class1Identifies the class of the item0 – Null or Test
1 – 1C for Retail
2 – 2C for Retail
3 – 3C for Retail
4 – Premium for Publishing Mail for Retail
5 – Deferred for Retail
6 – Air for Retail
7 – Surface for Retail
8 – Premium for Wholesale
9 – Standard for Wholesale
Supply Chain ID2 or 6Identifies the unique chain of customers involved in the mailing.
Consolidator Supply Chain ID are 2 digits.
All other 4-State SCIDs are 6 digits.
00 to 99
000000 to 999999
Item ID8Identifies the unique item within the
Supply Chain.
00000000 to 999999991234567812345678
Destination Post Card plus DPS9Contains the Postcode of the destination with DPSThe Postal Code and Delivery Point must comply with Postcode Address File Format.CW14LZ1F<space>CW14LZ1F<space>

For more information: Mailmark Technical Handbook.