Royal Mail 4-State Mailmark — Barcode Format Guide & Generator
Royal Mail 4-State Mailmark is a one-dimensional linear symbology in the Postal family. 4-state symbol with Reed-Solomon ECC; 22/26 characters. These codes appear on addressed mail, reply envelopes, parcels and trays — wherever the reader is a sorter, not a human.
- Category
- Postal
- Symbol
- Linear (1D) bars
- Data
- Plain text within the symbology’s character set and length limits
- Example
- 21B2254800659JW5O9QA6Y
Data format
Enter the payload as plain text. The encoder enforces each symbology’s character set and length rules, and rejects out-of-spec input with a clear message instead of silently producing a bad symbol.
Strengths and limitations
Strengths
- Purpose-built for high-speed postal and courier sorting machines.
- Prints reliably with ordinary office printers on plain paper labels.
Limitations
- Mainstream phones and retail scanners will not decode it — only the dedicated system that expects it.
Generate one in QrDeco
- Open QrDeco and choose Royal Mail 4-State Mailmark from the format list.
- Type or paste your data — for example 21B2254800659JW5O9QA6Y.
- Adjust size, colours, quiet zone or human-readable text in the style panel if you need them.
- Export an SVG or PDF for print, or a PNG for screens — generated locally in your browser, nothing is uploaded.
Scanning and printing tips
- Match the operator’s digit counts and prefixes exactly — sorters reject pieces whose data drifts from the specification.
- Print at the specified bar height and pitch for the operator’s reading equipment.
- Leave the quiet zones clear — blank space on both sides of the bars is part of the symbol.
- Print dark bars on a light background; red-only bars can vanish under red laser light.
- Keep the bars vertical to the scan direction and print at the symbol’s standard magnification.
Related formats
More from the Postal family, plus the family overview: