Seams and edges are the enemy
A barcode folded over an edge wrinkles, and a wrinkled code misreads. When one face genuinely cannot hold the whole label, FedEx allows a split: position the barcode on one side of the seam and the recipient’s information on the other, per fedex.com. Flat on a single face beats clever every time.
Tape the edges, never the code
Secure all four label edges so nothing lifts in transit, but leave the printed area, and above all the barcode, uncovered. A code a scanner cannot read sends your box on a detour through human hands, and human sorting is where days get lost.
Reused boxes need housekeeping
The USPS packing page, checked 2026-07-27, tells anyone reusing a carton to cover or black out all old logos, barcodes, shipping labels and addresses. One stray code from the box’s previous trip can win the scanner race and route your parcel into history.