What is Mailmark?

Postage costs change, franking machines need updating and the barcode on an envelope can feel like one more piece of postal jargon to work out.

Mailmark is Royal Mail technology designed to make business mail easier for its sorting systems to read and process.

Royal Mail invested more than £80 million in introducing Mailmark technology. The aim was to update traditional mail and franking services, improve processing and give businesses access to lower postage rates.

But what is Mailmark franking, how do its tracking services work and what does a business need before it can use the technology?

How does Mailmark franking work?

Mailmark franking updates the traditional method of franking business post by using machines that apply a two-dimensional barcode in the address area of an envelope.

The barcode contains information including the sender’s account number and mailing details.

This is easier for Royal Mail’s sorting equipment to read than older franking impressions, where machines need to recognise the printed account number.

For Royal Mail, that can make customer billing faster, more accurate and more efficient. Some of those efficiencies are passed on through lower postage rates for businesses using Mailmark franking.

Mailmark rates are also intended to encourage commercial mail senders to move away from older franking technology.

See the 2026 Royal Mail price changes

What are Mailmark tracking services?

Mailmark can also refer to services used to identify and process individual items as they move through the Royal Mail network.

This uses a different two-dimensional barcode applied by the sender. The barcode contains information about the recipient’s address, allowing Royal Mail’s sorting equipment to process the item using the information stored in the code.

This is more efficient than relying only on sorting machines to read every printed or handwritten address and postcode. It can also reduce the margin for error during sorting.

As with Mailmark franking, Royal Mail can pass some of the processing savings on to businesses using the service.

The information available will depend on the Mailmark service being used. Tracking or proof of postage should not be treated as proof that an item was delivered to its recipient.

What does a business need to use Mailmark?

Businesses that want to use Mailmark directly need software capable of generating the correct barcodes.

They also need to prepare and post their own mail, while making sure that every address matches the Royal Mail Postcode Address File, commonly known as PAF.

That can mean investing in new franking equipment, software, maintenance and internal mailing processes.

As a result, Mailmark has traditionally been used most by larger organisations processing hundreds of thousands of letters each year. They are more likely to have the volume, budget and infrastructure needed to support the investment.

Before buying a Mailmark franking machine, it is worth comparing more than the postage rate. Equipment hire, contracts, supplies, staff time and mail preparation all contribute to the real cost of sending business post.

Use the calculator below to estimate how your current mailing costs compare with Postworks Send.

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Please note: The numbers you see here are estimates based on 2026 UK mailing and franking costs. Every business is different, so your actual costs may vary a little - figures are for guidance only and not a formal quotation. Please speak to our Product Specialists for a tailored solution for your company.

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How Postworks makes Mailmark available to more businesses

Postworks works to make the benefits of Mailmark available to small and medium-sized businesses without asking them to invest in their own mailing equipment.

Customers upload their mail through the Postworks online platform. Postworks then checks the address against the Royal Mail Postcode Address File, prints the letter and hands it to Royal Mail for delivery.

The same process can be used by a business sending one letter or one thousand letters.

Customers can follow their letters through the Postworks process online. ClearSend® also provides certified proof that an item has entered the Royal Mail network.

This provides a useful postage record, but it does not prove that the letter was delivered to the recipient.

For businesses that want the benefits of Mailmark without another machine, contract or postal process to manage, Postworks provides a simpler way to send letters online.

Explore Postworks SendWatch the ClearSend video

The future of Mailmark and online business post

Mailmark was an important step in updating older methods of sending and processing business mail.

However, direct access has mostly suited larger companies with the mailing volumes, finances and infrastructure needed to invest in the technology.

At the time this article was originally published, businesses generated around 90% of mail in the UK. Postworks’ aim was to make postal innovation, better visibility and more efficient processing available to organisations regardless of their size.

That means a small business can send sales letters from a PC, while a larger organisation can manage regular business post without running its own post room or franking operation.

Before buying a Mailmark franking machine, compare the full cost of the process and consider whether sending letters online could take more of the work off your team.