About Royal Mail Mailmark
Mailmark is Royal Mail's current machine-readable marking system for business mail. The data string carries format, version ID, class, supply chain ID, item ID and the destination postcode with DPS. We render the Mailmark symbol in its Data Matrix form (type 7, 9 or 29); the 4-state variant requires the same data in a Royal Mail licensed encoder.
Data format
Mailmark data string (starts with JGB), at least 45 characters.
Example: JGB 012100123412345678AB19XY1A 0
Postal Codes
Postal barcodes are used by postal operators for automatic sorting and tracking. Many are 4-state codes (ascender, descender, tracker, full bars) that fit even in narrow address areas.
Frequently asked questions about Royal Mail Mailmark
Is the Royal Mail Mailmark generator really free?
Yes. You can create as many Royal Mail Mailmark barcodes as you like and download them as PNG or SVG – no registration, no watermark, commercial use included.
What resolution does the Royal Mail Mailmark barcode have?
PNG files are generated with adjustable module width and up to 600 DPI. For print we recommend the lossless SVG vector format which scales without any quality loss.
Is my data stored?
No. The barcode content is only processed to render the image and is not stored. We only count anonymously how often a barcode type is used.
Can I embed Royal Mail Mailmark barcodes in my website or software?
Yes. Every barcode has a stable image URL (see “Embed HTML”) which you can use in websites, label software or spreadsheets.