What does Mailsort look like today?

If you’re planning a large direct mail campaign, postage is likely to be one of the biggest costs involved. While the standalone Mailsort service has largely been replaced by Mailmark®, the principles behind it still play an important role in how Royal Mail calculates bulk mail discounts today.

The underlying concept of pre-sorting mail remains central to how these services work. Preparing mail in line with Royal Mail’s sorting requirements still enables discounted postage rates.

Understanding how mail sorting works and how it fits within modern Mailmark® services can help businesses make smarter decisions about print, fulfilment and postage costs.

What is Mailsort?

Mailsort was originally developed by Royal Mail to offer discounted postage rates for bulk mail that’s been prepared and sorted before entering the postal network. Although Mailmark® has now replaced many of the older Mailsort processes and technical standards, mail sorting itself is still a key part of Business Mail and Advertising Mail services.

The process involves organising mail by postcode, grouping items into defined batches and preparing them according to Royal Mail’s specifications. By doing some of this work in advance, mail moves through the network more efficiently, allowing Royal Mail to offer lower postage rates in return.

Today, Mailmark® handles much of this process automatically with unique 2D barcodes on individual mail pieces. However, there are still situations where more traditional sorting methods are relevant, particularly for items that cannot be machine-read. This is sometimes referred to as High Sort mail and can apply to items wrapped in polythene, mail using certain fonts or pieces that do not meet barcode standards.

These services are typically used for:

Direct mail marketing
Customer communications
Statements and bills
Charity appeals
Membership mailings

In short, businesses sending mail at scale can still benefit from the efficiencies created by mail sorting, even though Mailmark® is now the primary service framework.

How does sorting mail work?

Modern bulk mail preparation is about structuring mail to work efficiently within Royal Mail’s automated systems. While the technology has evolved, many of the preparation stages remain similar to the traditional Mailsort process. Here’s a simplified breakdown:

Data preparation: Your address data needs to be clean, accurate and formatted correctly. The data is validated and standardised against Royal Mail’s postcode database to ensure it can be sorted efficiently.
Sorting by postcode: Once the data is ready, addresses are sorted into postcode groups. These are then organised into specific sequences, depending on the level of detail required.
Bundling and labelling: Printed items are grouped into bundles based on their sort order. Each bundle is clearly labelled, showing where it fits within the overall mailing structure.
Bagging: Bundles are placed into mailbags or trays, again following strict guidelines. Each container is labelled so Royal Mail can route it quickly through their network.
Handover to Royal Mail: The fully prepared mailing is delivered to a designated mail centre. Because it’s already sorted, it moves through the system more efficiently than standard mail.

The more work done upfront, the greater the potential savings. That’s why sorting mail isn’t just about postage – it’s closely tied to data quality, print production and fulfilment.

Why is this used for cost control?

Postage is often one of the highest costs in a direct mail campaign. Luckily, sorting mail helps bring that cost down without compromising on reach. The key benefits include:

Lower postage rates

Because you’re reducing the amount of sorting Royal Mail needs to do, you qualify for discounted pricing. For large campaigns, this can make a significant difference to overall costs.

Predictable delivery windows

It operates on defined delivery speeds, giving you a clear expectation of when your mail will land. That consistency is useful when planning campaigns around key dates. Here are the options:

Mailsort 1 (or 1st Class Sorting): Aims for delivery the next working day.
Mailsort 2 (or 2nd Class Sorting): Aims for delivery within three working days.
Mailsort 3 (or Economy): Aims for delivery within six working days.

Better use of your budget

Savings on postage can be reinvested elsewhere, whether that’s improving creative, increasing volume or testing new audience segments.

Ask your mailing house to advise you on quantities below 1,000 large letters or 4,000 standard letters, as Mailmark® discounts can still apply.

When is Mailsort the right choice?

If you’re sending a minimum of 1,000 large letters or 4,000 standard letters, Mailsort could be an effective solution.

It’s typically suitable when:

You’re sending large volumes
You have good-quality address data – correctly formatted postcodes and complete address information
You’re looking to reduce unit costs at scale

It cannot be used if:

Volumes are low – less than 1,000 large letters or 4,000 standard letters
Data is incomplete

In those cases, alternative services will be more appropriate – such as unsorted Mailmark®, or Advertising Mail products.

What preparation is involved?

One of the reasons Mailsort delivers savings is because of the preparation required upfront. Ensuring your data is compliant isn’t just about sorting envelopes, it’s a structured process that touches multiple parts of your campaign.

Key preparation steps include:

Data cleansing and validation: Addresses must be accurate and formatted to match Royal Mail’s Postcode Address File (PAF).
Correct formatting: Addresses should be printed and formatted to enable machine reading.
De-duplication: Removing duplicate records avoids sending multiple items to the same recipient, saving both print and postage costs, as well as improving data accuracy.
Geographic sortation: Data is sorted and ordered before printing and the Mailsort order is then maintained throughout printing and fulfilment, right through to bagging and labelling.
Suppression checks: Screening against preference services (such as the Mailing Preference Service) helps maintain compliance and protects your brand.
Print and personalisation workflow: Mail has to be printed to match the sorted order, which often requires coordinated data and print workflows.
Packaging and labelling compliance: Everything from bundle sizes to label placement must meet Royal Mail specifications.

All of this might sound overwhelming, but the key is having the right help in place.

The role of a mailing house when using Mailsort

This is where a mailing house, like The Mailing People, becomes essential. Mailsort isn’t just a postage option, it’s a coordinated operation that spans data, print, fulfilment and logistics.

Here’s how an expert partner can support your campaign:

Data handling and optimisation: They clean, validate and prepare your data, making sure it meets Mailsort requirements and is ready for sorting.
Sorting and software expertise: Specialist software is used to generate the correct sortation, ensuring maximum postage discounts are achieved.
Print and fulfilment coordination: Mail is printed, enclosed and prepared in the correct sequence, avoiding errors and delays.
Compliance and accuracy: Mailing houses ensure all Royal Mail guidelines are followed, reducing the risk of surcharges or rejected mail.
Postage management: By understanding the different Mailsort options and thresholds, they can advise on the most cost-effective approach for your campaign.
End-to-end efficiency: From data to delivery, everything is managed as a single process, which improves accuracy and keeps timelines on track.

In practical terms, this means fewer internal resources are required from your side and a smoother path from concept to doorstep.

Delivering campaigns more efficiently

Mailsort is ultimately about working smarter with your mail. By investing in preparation and structure upfront, you gain efficiency, reduce costs and maintain reliable delivery.

If you run regular or large-scale campaigns, those savings add up quickly. But just as importantly, it creates a more controlled and predictable process, something that’s often just as valuable as the cost reduction itself.

With the right data, the right volumes and our help, Mailsort becomes a practical tool to make your direct mail work harder, without increasing your budget. If you’re looking for end-to-end support on your next direct mail campaign, reach out to us.

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