[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-1-en-105":3,"doc-seo-279744-105":53,"doc-detail-279744-en":119},{"code":4,"msg":5,"data":6},0,"success",[7,14,19,24,29,34,39,44,49],{"id":8,"doc_module":9,"doc_module_name":10,"category_name":11,"show_sort_weight":12,"slug":13},11,1,"Template","Presentations",90,"presentations",{"id":15,"doc_module":9,"doc_module_name":10,"category_name":16,"show_sort_weight":17,"slug":18},12,"Resumes",80,"resumes",{"id":20,"doc_module":9,"doc_module_name":10,"category_name":21,"show_sort_weight":22,"slug":23},14,"Invoices",70,"invoices",{"id":25,"doc_module":9,"doc_module_name":10,"category_name":26,"show_sort_weight":27,"slug":28},15,"Posters",60,"posters",{"id":30,"doc_module":9,"doc_module_name":10,"category_name":31,"show_sort_weight":32,"slug":33},16,"Social Media",50,"social-media",{"id":35,"doc_module":9,"doc_module_name":10,"category_name":36,"show_sort_weight":37,"slug":38},17,"Forms",40,"forms",{"id":40,"doc_module":9,"doc_module_name":10,"category_name":41,"show_sort_weight":42,"slug":43},18,"Letters",30,"letters",{"id":45,"doc_module":9,"doc_module_name":10,"category_name":46,"show_sort_weight":47,"slug":48},21,"Paper Templates",5,"papers-templates",{"id":50,"doc_module":9,"doc_module_name":10,"category_name":51,"show_sort_weight":4,"slug":52},158,"General","general-158",{"code":4,"msg":54,"data":55},"ok",{"site_id":56,"language":57,"slug":58,"title":59,"keywords":60,"description":61,"schema_data":62,"social_meta":112,"head_meta":114,"extra_data":116,"updated_unix":118},105,"en","mailmark-letters-specification-requirements","Mailmark Letters - Specification Requirements","","Mailmark Letters specification requirements define the physical design and mail characteristics needed for Royal Mail Mailmark letter processing machines to read and process letters at high speed. The requirements cover size and shape, thickness and weight, inserts and lateral movement limits, material and envelope construction, sealing and flap positioning, and printing and finishing conditions for digitally printed items. Each requirement is classified as Mandatory (M), Recommended High Risk (H), or Recommended Low Risk (L), with guidance on risks, surcharges, and potential machine damage.",{"@graph":63,"@context":111},[64,80,102],{"@type":65,"itemListElement":66},"BreadcrumbList",[67,71,74,77],{"item":68,"name":69,"@type":70,"position":9},"https://docshare.wps.com","Home","ListItem",{"item":72,"name":10,"@type":70,"position":73},"https://docshare.wps.com/template/",2,{"item":75,"name":41,"@type":70,"position":76},"https://docshare.wps.com/template/letters/",3,{"item":78,"name":59,"@type":70,"position":79},"https://docshare.wps.com/template/mailmark-letters-specification-requirements/279744/",4,{"url":78,"name":59,"@type":81,"image":82,"author":87,"headline":59,"publisher":90,"fileFormat":93,"inLanguage":57,"description":61,"dateModified":94,"datePublished":95,"encodingFormat":93,"isAccessibleForFree":96,"interactionStatistic":97},"DigitalDocument",{"url":83,"@type":84,"width":85,"height":86},"https://docshare.wps.com/thumbnails/mailmark-letters-specification-requirements/279744.png","ImageObject",442,249,{"name":88,"@type":89},"Theodore","Person",{"url":68,"name":91,"@type":92},"DocShare","Organization","application/pdf","2026-10-19","2026-09-16",true,{"@type":98,"interactionType":99,"userInteractionCount":101},"InteractionCounter",{"@type":100},"ViewAction",6,{"@type":103,"mainEntity":104},"FAQPage",[105],{"name":106,"@type":107,"acceptedAnswer":108},"What guidance applies to digitally printed mail items?","Question",{"text":109,"@type":110},"Digitally printed pigments may rub off, transfer, crack, or become marked during manual and automated handling. The use of a UV-cured varnish is recommended to reduce wear, applied only to the non-address side to avoid making items unmachineable.","Answer","https://schema.org",{"og:url":78,"og:type":113,"og:title":59,"og:site_name":91,"og:description":61},"article",{"robots":115,"canonical":78},"index,follow",{"doc_id":117,"site_id":56},279744,1791408646,{"code":4,"msg":5,"data":120},{"doc_id":117,"user_id":121,"nickname":88,"user_avatar":122,"doc_module":9,"category_id":40,"category_name":41,"doc_title":59,"doc_description":61,"doc_content":123,"file_id":124,"file_url":125,"file_type":126,"file_size":127,"view_count":101,"is_deleted":4,"is_public":9,"is_downloadable":9,"audit_status":9,"page_count":128,"language":129,"language_code":57,"site_id":56,"html_lang":57,"table_of_contents":130,"faqs":131,"seo_title":132,"seo_description":61,"update_tm":133,"read_time":15},7971461740886,"https://ap-avatar.wpscdn.com/davatar_3d24733baf745e90a7e4bdd5f77d97b2","Mailmark Letters – Specification Requirements  \nThe document sets out physical design, Indicium, addressing, barcoding and other Royal Mail Mailmark specifications that are required when posting Letters using Mailmark.  \nThe document is designed to ensure that Royal Mail Letter processing machines can process and read Letters effectively at high speed, without the need for manual or other intervention. Each specification requirementset out in this Appendix M has been assessed and is categorised as either ‘Mandatory’ (M), or ‘Recommended High Risk’ (H) or ‘Recommended Low Risk (L)’:  \n• Letters that fail to meet the ‘Mandatory’ requirements are regarded as unmachineable and are very likely to have Surcharges applied.  \n• Letters which fail to meet the requirements that are identified as ‘Recommended-High Risk’have a higher likelihood of performing poorly through our processing machines. Letters that fail to meet these requirements are more likely to have Surcharges applied and may become damaged in our processing machines.  \n• Letters which fail to meet the requirements that are identified as ‘Recommended-Low Risk’, may perform poorly through our processing machines. However, the risk is lower than that posed by failure to meet the ‘Recommended High Risk’ specifications and there is less chance of Letters being damaged or Surcharges being applied.  \nWe have provided guidance footnotes that explain the risks associated with not meeting the ‘Recommended’requirements.  \nAt the bottom of the document we have also provided all of the Figures which are referenced throughout the document and which provide illustrative examples of the specification requirements.  \n1. Physical  \n\n| Category |  | Specification Requirement | M/R |  |  |\n| --- | --- | --- | --- | --- | --- |\n| \u003Cbr>Size & Shape | Shape | Rectangular or square with straight sides and 90o corners | M |  |  |\n|  | Orientation | Landscape or portrait | M |  |  |\n|  | Size\u003Cbr>(H x L x D) | Rectangular Minimum – 90mm x 140mm, Maximum – 165mm x 240mm\u003Cbr>Square Minimum – 140mm x 140mm, Maximum – 165mm x 165mm | M |  |  |\n|  | Thickness | Minimum – 0. 25mm, Maximum – 5mm | M |  |  |\n|  | Weight | Maximum – 100g | M |  |  |\n|  | Content / Inserts | • One or two standard size staples (maximum 24mm x 6mm) or paper clips (maximum 23mm long) may be inserted in the Letter.\u003Cbr>• Other metal objects such as keys, pens, coins etc. must not be placed in the Letter.\u003Cbr>• Inserts other than paper that are placed in an envelope should be fixed in position and attached to the largest paper [insert. e.g. bank](insert. e.g. bank) cards.\u003Cbr>• The spines on booklet inserts should be located on the reference edge 2. | M\u003Cbr>M\u003Cbr>H\u003Cbr>L | 1\u003Cbr>3 | |\n|  | Lateral Movement | There are limitations on the lateral movement space that the insert may have. These are dependent upon the thickness of the Letter and apply to the largest paper insert (see Figure 1):\u003Cbr>• Where the thickness is 2mm – 5mm the lateral movement should be no more than 20mm. | \u003Cbr>H 4 |  |  |\n\n1 Lowers the risk of moving inserts breaking through the Letter edges.  \n2The reference edge is a fold on a particular edge of the Letter, which enables it to be processed through the machines efficiently. The reference edge is the edge beneath the address for landscape rectangular and square Letters, and the long edge to the left of the address for portrait Letters.  \n3 This reduces the potential for mail damage following jams.  \n\n| Category |  | Specification Requirement | M/R |  |\n| --- | --- | --- | --- | --- |\n| |  | • Where the thickness is 0. 25mm – 2mm, the lateral movement should be no more than 30mm. | L 4 |  |\n|  | Flexibility | Each Letter must be capable of being transported around a pulley with a radius of 140mm with a max force of 26 N (See Figure 2) . | M |  |\n| \u003Cbr>E l C t tinve ope o s ruc o & Design | Material | Envelopes must be made from paper only and have NO open apertures 5 | M |  |\n|  | Flaps | The opening flap may fold to ","cbCaijRYChmX1tTA","https://ap.wps.com/l/cbCaijRYChmX1tTA","pdf",3143115,33,"English","# Physical\n## Size & Shape\n## Content / Inserts\n## Flexibility\n## Envelope & Construction\n## Sealing\n## Paper Characteristics\n## Digitally Printed Mail","[{\"question\":\"What guidance applies to digitally printed mail items?\",\"answer\":\"Digitally printed pigments may rub off, transfer, crack, or become marked during manual and automated handling. The use of a UV-cured varnish is recommended to reduce wear, applied only to the non-address side to avoid making items unmachineable.\"}]","Mailmark Letters - Specification Requirements | PDF",1789526548]