A shipping label should show the recipient’s address large and centered, the sender’s return address in the upper left, service and postage information in the upper right, and a scannable barcode with its tracking number printed below it. The whole thing prints in black on a white background, sits flat on the largest side of the package, and follows a 4-by-6-inch format that USPS, UPS, and FedEx all recognize. Get those pieces right and automated sorting equipment reads the label in a fraction of a second. Get them wrong and the package stalls, gets returned, or hits you with an address correction fee.
What Goes on the Label
The delivery address is the most important block of text. USPS requires the recipient’s name, the street address with any apartment or suite number, and the city, state, and ZIP code.1United States Postal Service. 602 Quick Service Guide UPS and FedEx follow the same pattern and also request a phone number so drivers can call if they can’t find the location or need a gate code. Leaving that number off a FedEx or UPS shipment won’t stop the package from moving, but it can turn into a failed delivery attempt that adds a day or more.
The return address goes in the upper left corner. USPS requires one on nearly every package type, including Priority Mail, USPS Ground Advantage, Parcel Select, insured mail, and anything containing hazardous or perishable contents.2United States Postal Service. 602 Addressing – Postal Explorer Even when it isn’t strictly required, skipping it leaves the carrier no way to send the package back if delivery fails. A wrong or incomplete address is actually worse than a missing one, because the carrier may correct it and bill you. UPS charges $23.50 per address correction, and FedEx charges $25.50 per correction as of 2026.3FedEx. 2026 Changes to FedEx Surcharges and Fees
A service banner tells handlers how urgently the package needs to move. On USPS labels the text “USPS PRIORITY MAIL” or the appropriate service name must be printed in at least 20-point bold type, centered within a banner bordered by separator lines. Delivery confirmation text must be at least 12-point bold, and human-readable characters beneath barcodes must be at least 10-point bold.4Federal Register. Shipping Label Requirements Those minimums exist because sorting facilities process thousands of packages an hour and undersized text slows the line down.
The barcode is what links the physical box to the carrier’s tracking system. For USPS shipments, the Intelligent Mail package barcode encodes routing data that lets automated equipment sort and track packages from origin to the delivering post office. Each package must carry a unique barcode tied to an electronic shipping record with the destination address and a validated ZIP code.5PostalPro. Intelligent Mail Package Barcode (IMpb) UPS and FedEx use their own barcode formats, but the principle is the same. An alphanumeric tracking number prints directly below the barcode as a manual fallback so a worker can key it in if scanning fails. A separate postal routing barcode may also appear, encoding the ZIP or ZIP+4 to speed automated sorting.6United States Postal Service. 204 Barcode Standards – Postal Explorer
Where Each Element Sits
Shipping labels follow a consistent visual hierarchy across carriers. Return address upper left. Recipient address in the center, printed larger than anything else so it’s the first thing a driver or sorting camera sees. Postage and service indicators upper right. Barcodes along the bottom half.
Contrast matters more than most people think. Black text on a white background is the standard because optical scanners are calibrated for that combination. Colored backgrounds, faded ink, or patterned packaging visible through a thin label all raise the odds of a scanning failure. If the printout looks gray or the edges of the barcode bars look fuzzy, reprint before you ship.
Size, Printing, and Where to Stick It
The standard shipping label is 4 by 6 inches. That’s the default for USPS, FedEx, and UPS, and nearly every shipping platform and label printer is built around it. The format leaves enough room for the address blocks, barcodes, and service markings without shrinking anything to the point where scanners struggle. FedEx also accepts 8.5-by-11-inch labels printed on laser printers, but the 4-by-6 format is overwhelmingly the norm.
For print method, direct thermal printers are the industry workhorse. They produce sharp, high-contrast barcodes without ink or toner, so there’s no smudging and almost no maintenance. Inkjet printers work for occasional shipments but tend to produce softer edges on barcodes, and the ink can bleed if the label gets wet. If you ship regularly, a thermal printer pays for itself quickly in reliability.
Where you stick the label matters as much as what’s on it. USPS requires the label to sit squarely on the largest flat surface of the package, with the barcode at least one inch from any edge.7United States Postal Service. 202 Elements on the Face of a Mailpiece – Postal Explorer Placing a label across a seam, edge, or corner warps the barcode and almost guarantees a scan failure. Clean and dry the surface first so the adhesive bonds permanently.
One mistake trips up a lot of first-time shippers: covering the barcode with clear packing tape. It looks like smart protection, but USPS scanning equipment cannot reliably read barcodes through tape because the plastic creates glare that blinds the optical readers.8United States Postal Service. USPS Postal Bulletin – Barcode Scanning If you need to weatherproof a label, cover the address text but leave the barcode exposed, or use a clear adhesive label pouch designed for shipping.
Fragile, Orientation, and Handling Marks
A “Fragile” sticker feels like the right move for anything breakable, but it does less than most shippers assume. Standard fragile stickers are visual cues for manual handling, not a contract for different treatment. Unless you’ve paid for a special-handling service, they don’t trigger anything different from UPS, FedEx, or USPS. USPS discontinued its Special Handling — Fragile service entirely in 2022.9United States Postal Service. Fragile Handling Dropped
They still help during the manual portions of the journey, like loading and last-mile delivery. If you use them, place them on at least two adjacent sides of the box so they’re visible no matter how the package is stacked, and pair them with “This Side Up” arrows when the contents depend on staying in a specific orientation.
Extra Labeling for Lithium Batteries and Hazmat
If you’re shipping anything classified as hazardous, label requirements jump from best practice to federal law. This catches more people than expected, because lithium batteries fall under hazardous materials rules, and lithium batteries live inside laptops, phones, power banks, and e-cigarettes.
Packages containing lithium batteries must display a standardized lithium battery mark: a rectangle at least 100 millimeters wide by 100 millimeters high with red hatched edging and black symbols on a white background. The mark must include the correct UN identification number (UN3480 for lithium ion batteries alone, UN3481 when they’re packed with equipment, and corresponding numbers for lithium metal batteries). Packages that can’t fit the full-size mark may use a smaller version of 100 by 70 millimeters.10eCFR. 49 CFR 173.185 – Lithium Cells and Batteries Lithium batteries that can’t travel on passenger aircraft also need specific warning text in letters at least 6 millimeters high, or 12 millimeters for packages over 66 pounds.
The penalties for getting hazmat labeling wrong are severe. Federal law sets the base civil penalty for violating hazardous materials transportation rules at up to $75,000 per violation, rising to $175,000 where the violation results in death, serious injury, or major property destruction.11Office of the Law Revision Counsel. 49 USC 5123 – Civil Penalty Those are the statutory base amounts; inflation adjustments push the current maximums higher. Enforcement isn’t limited to commercial shippers. An individual selling a used laptop online can face action if the battery isn’t properly declared and labeled.
International Shipments
Crossing a border adds a customs declaration to the label. For USPS international shipments, packages valued at $400 or less use customs form 2976 (the smaller CN22 declaration). Items over $400 generally require the more detailed CN23 form, and the specific form depends on the mail class and destination country. Any package containing merchandise needs a customs form regardless of value, and any item weighing more than 16 ounces requires one regardless of contents.12United States Postal Service. 123 Customs Forms and Online Shipping Labels – Postal Explorer
The declaration must accurately describe what’s inside, its value, and its country of origin. Undervaluing contents to reduce duties is illegal in virtually every destination country and can get the package seized. Most shipping platforms generate customs forms automatically when you enter the package details, but the accuracy of what you declare is on you.
UPS and FedEx handle customs paperwork through their own electronic systems, generating commercial invoices rather than postal customs forms. The information required is the same: contents description, declared value, harmonized tariff codes for commercial shipments, and full sender and recipient contact details including phone numbers.
No Printer? QR Code Options
If you don’t have a printer at home, you’re not stuck paying a retail counter to print the label for you. USPS Label Broker lets you generate a QR code on your phone, bring the sealed package to the Post Office, and have the clerk scan the code and print the label on the spot.13United States Postal Service. USPS Label Broker FedEx offers a similar mobile workflow through its app, and UPS runs its own version through UPS Access Point locations. The printed label still follows all the same formatting and barcode standards. The QR code just moves your shipping data to the printer at the drop-off point.