Royal Mail Mailmark 4-State Generator

What Is a Royal Mail Mailmark 4-State Barcode?

The royal mail mailmark 4-state generator in Barcode Mint produces the newer of Royal Mail's two four-state postal barcode formats, introduced as part of the wider Mailmark program that also includes a 2D data matrix variant. Where the older RM4SCC barcode was built purely for postcode-based sortation, Mailmark 4-State keeps the same visual height-modulated bar structure but is designed to sit alongside Royal Mail's Mailmark tracking and mail-class infrastructure.

Visually, it looks like the row of short, uneven bars familiar from any UK 4-state postal code — full bars, ascenders, descenders, and trackers — printed on the envelope or wrapper. Mailers who need both automated sortation and Mailmark-level visibility into their mail's journey through the network use this format instead of, or alongside, the 2D Mailmark barcode.

How Mailmark 4-State Encodes Data

Like RM4SCC, Mailmark 4-State uses the four-state bar alphabet — each bar printed as a full bar, ascender, descender, or tracker — with a start character, stop character, and check character framing the message for error detection. The core routing payload is the same kind of data as RM4SCC: a UK postcode plus delivery point suffix, which sorting equipment uses to route the item to a specific address.

What sets Mailmark 4-State apart in Royal Mail's broader system is its role within the Mailmark program: mail carrying a Mailmark barcode (whether 4-state or 2D) is registered against a mailer's Mailmark account, letting Royal Mail track service performance and mail class compliance at a program level, even though the 4-state variant itself still encodes postcode and DPS in the barcode bars.

Technical Specifications

Mailmark 4-State shares its character set and four-state bar mechanics with RM4SCC — encoding the alphanumeric characters used in UK postcodes and delivery point suffixes, framed by start/stop/check characters. The practical difference is contextual rather than structural: Mailmark 4-State is used specifically within Royal Mail's Mailmark mailing framework, which requires mailers to hold a Mailmark licence and register their mail items for tracking and reporting purposes.

Barcode Mint renders Mailmark 4-State using the same reliable 4-state postal engine as RM4SCC, so the bar geometry, height ratios, and print tolerances you need to hit are consistent between the two formats — the distinction that matters is which Royal Mail service and account you're printing against.

Where Mailmark 4-State Barcodes Are Used

This format applies specifically to UK mail sent through Royal Mail's Mailmark program:

• Mailmark-registered bulk mail — businesses enrolled in Royal Mail's Mailmark mailing services print this barcode to combine sortation with program-level tracking.
• Transactional and marketing mail — UK companies sending statements, renewals, or direct mail through Mailmark-compliant channels use it for both routing and delivery reporting.
• Access and wholesale mail operators — downstream access providers handling UK mail on Royal Mail's network apply Mailmark barcodes to meet program requirements.
• High-volume transactional mailers — organizations that want visibility into induction and delivery timing alongside standard postcode sortation.

How to Create a Mailmark 4-State Barcode in Barcode Mint

Select Royal Mail Mailmark 4-State from the Postal Code group in the symbology list. Enter the UK postcode and delivery point suffix data for your mail piece — the live preview draws the four-state bar pattern immediately so you can check it before exporting. From there:

• Adjust bar height and spacing to match the placement zone required for Mailmark-compliant mail pieces.
• Keep the barcode solid black on a light background; Royal Mail's optical readers need high contrast, the same as for standard RM4SCC.
• Export as PNG or SVG for insertion into your mail production template, or use Copy to paste it directly into design or print software.
• Use the bulk CSV → ZIP/PDF tool to generate one barcode per recipient across a full mailing list in a single export.
• Call the REST API — /barcode?type=mailmark4state&data=YOURPOSTCODEDPS — to generate barcodes on demand from a mail production or fulfillment system.

Printing and Scanning Best Practices

Mailmark 4-State feeds the same high-speed automated sortation equipment as RM4SCC, so the same print discipline applies, with added weight given its role in a tracked mail program:

• Position the barcode exactly where Royal Mail's Mailmark specification requires for your mail format, since placement errors can affect both sortation and tracking accuracy.
• Print in solid black ink on light, matte stock — avoid glossy finishes and low-contrast color schemes that scatter light from postal optical sensors.
• Preserve full bar height fidelity; the four-state distinction between ascenders, descenders, and trackers is easy to blur on low-resolution thermal or inkjet output.
• Leave a clear quiet zone around the barcode, free of other printed elements.
• Run a verification pass before a production mailing — Mailmark compliance typically requires proof that barcodes meet Royal Mail's read-rate standards before large volumes are inducted into the network.

Mailmark 4-State vs Related Postal Codes

Mailmark 4-State and RM4SCC look identical on the page and use the same bar mechanics, but Mailmark 4-State is tied to Royal Mail's Mailmark program for mailers who want tracking and reporting on top of sortation, while RM4SCC is the simpler legacy format for pure postcode-based routing. Royal Mail's separate Mailmark 2D barcode is a data matrix symbol that can carry far more information than any 4-state format, at the cost of needing 2D imaging scanners rather than simple bar-height readers. Outside the UK, Australia Post's 4-State Customer Barcode and Japan Post's barcode apply the same four-state visual concept to entirely different national postal systems and are not compatible with UK Mailmark requirements.

Common uses

• Mailmark-registered bulk mail requiring routing and tracking
• UK transactional and statement mail through Mailmark-compliant channels
• Downstream access and wholesale mail operator handling
• High-volume marketing mail needing delivery performance reporting
• UK mail production workflows migrating from legacy RM4SCC

Frequently asked questions

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