Mailing Intelligence Center™
USPS mailing guides, in plain language
The standards that decide what your piece costs and whether it mails at all: sizes, tabbing, addressing, automation, EDDM, and drop shipment. Written from the USPS Domestic Mail Manual by a USPS Full-Service Certified mail service provider, with no jargon and nothing to download.
Every guide
USPS Mail Classes Explained
First-Class, Marketing Mail, Nonprofit, Bound Printed Matter, and Media Mail: what each class is for, what it can contain, and how to choose.
Postcard, Letter, Flat, or Parcel: USPS Size Limits
The exact dimensions that decide whether your piece prices as a postcard, letter, flat, or parcel, plus the nonmachinable surcharge list.
Folded Self-Mailers and Tabbing Requirements
How many tabs a folded self-mailer needs, where they go, fold orientation, paper weight minimums, and when tabbing does not apply.
Mailing Booklets: Size, Spine, and Tabbing Rules
How a bound booklet mails: letter versus flat thresholds, spine orientation, tab count by weight, and paper stock minimums.
Automation and Presort: How to Earn the Lowest Postage
What machinable, nonmachinable, and automation mean, the presort minimums, and the requirements that unlock the lowest per-piece prices.
Addressing, CASS, and Move Update Requirements
CASS processing, ZIP+4 and delivery point coding, the Move Update rule, and ancillary service endorsements for undeliverable mail.
Preparing a Mailing List
How to format a mailing list, why CASS and Move Update matter, deduplication and householding, and what drives the price your list qualifies for.
Designing Artwork That Mails Correctly
Address block placement, the barcode clear zone, indicia position, machinable aspect ratios, and where tabs and folds can and cannot go.
EDDM: Every Door Direct Mail Requirements
EDDM size and weight rules, Retail versus BMEU, the daily piece cap, bundling, and when saturation mail beats a mailing list.
Drop Shipment and Destination Entry Discounts
What DNDC, DSCF, and DDU entry mean, how destination entry lowers postage, and when the freight cost is worth the discount.
USPS Delivery Times by Mail Class
Service standards for First-Class, Marketing Mail, Priority, Ground Advantage, and Media Mail, and how to plan a drop date around them.
Shipping Parcels: Ground Advantage, Priority, and Express
When a piece ships instead of mails, service size and weight limits, flat rate and cubic pricing, and how dimensional weight is billed.
USPS Extra Services: Certified, Registered, and Tracking
Certified Mail, Return Receipt, Registered Mail, Certificate of Mailing, Signature Confirmation, and insurance, and which class each attaches to.
Reply Mail: Courtesy, Business, and Qualified Business Reply
CRM, BRM, and QBRM compared: who pays return postage, what each requires, and how to choose a reply device for your campaign.
Postage Payment, Permits, and Indicia
Permit imprints, meters, and precanceled stamps, whether you need your own permit, and the postage statements that accompany a bulk mailing.
Intelligent Mail Barcode and Informed Delivery
What the IMb encodes, why placement and the clear zone matter, what Full-Service requires, and how an Informed Delivery campaign works.
Nonprofit Mail: Eligibility and Authorization
Which organizations qualify for nonprofit postage, how to apply with PS Form 3624, and the content restrictions that apply.
Political Mail and Official Election Mail
The difference between Political Mail and Official Election Mail, the tags and logos each uses, and how to plan around an election cycle.
Still not sure?
Ask the Plavidian Mail Expert a question in plain English and get an answer grounded in these same standards, or send us the piece and we will confirm it before you print.