A handmade card can be designed like a postcard without meeting the postal category you intended to pay for. Before printing a stack or buying postage, compare the finished mailpiece—not only the artwork file—with the current USPS requirements for the actual domestic service. Dimensions, material and attachments matter together. This guide promises no current rate, mailability decision or delivery date.

Read the retail card standard, not a general size suggestion

USPS’ retail physical standards require cards claimed at card prices to be rectangular, at least 3.5 inches high by 5 inches long and 0.007 inch thick, and no more than 4.25 inches high by 6 inches long and 0.016 inch thick. The same section includes paper/stock and attachment requirements. Dimensions are not the whole eligibility decision.

Keep the actual finished length, height, thickness and material with the intended service/category. A design template’s name or a seller’s postcard description does not establish that the piece you produce meets those conditions. Commercial and other mailing rules should not be silently substituted for this retail example.

An original oversized-design example

Imagine an unmade design planned at 7 inches long by 5 inches high. Those dimensions exceed the stated retail card maximums. That observation does not determine the complete alternative mailing category, price or whether every proposed material can be mailed. Ask USPS about the actual finished design before treating it as a postage-ready card.

For a useful design note, separate the artwork dimensions from the eventual physical stock, any layers/attachments and the address side. Record what is known and what needs confirmation. Adding a raised decoration after choosing postage can change the physical piece you are asking the postal service to handle.

Confirm the piece before the quantity purchase

USPS describes uniform paper/cardstock and identifies acceptable and unacceptable attachment conditions. Do not assume that every glued embellishment, uneven layer or non-paper object qualifies merely because the overall rectangle is small enough. Follow the actual current standard and obtain the relevant postal advice when uncertain.

Before paying for bulk printing or decorative supplies, resolve the mailpiece/category questions and the actual postage for the intended service. Keep the confirmed arrangement with your design record. No card was manufactured, measured or mailed here; the practical output is an informed production question that can prevent a beautiful paper project from depending on an unsupported rate assumption.

Sources & further reading

Published sources for the details and examples discussed in this story.