Use 4x6 labels for carrier shipping labels. The label-printer formats on eBay, Etsy and Shopify are 4 x 6 inches, and USPS Click-N-Ship labels print at about 4 x 6. None of them lists a 3x5 format, and eBay’s only smaller option is a 2 x 7 in format for USPS labels (see the standard shipping label size table for every format they do offer). Buy 3x5 labels only for labels you lay out at 3 x 5 yourself, such as return-address, contents or branded labels, not for postage.

Why 3x5 Is a Poor Fit for Carrier Labels

A 4 x 6 label fits on 3 x 5 stock only if you scale it to 75 percent, because the 3-inch width is the limit (6 x 0.75 = 4.5 inches tall). Everything on the label shrinks by a quarter, including the barcode.

USPS sets minimums for the package barcode in the Domestic Mail Manual (DMM 204, section 2.2.5): narrow bars and spaces must be at least 0.013 inch wide, with 0.015 to 0.017 inch preferred, and bars at least 0.75 inch tall. A barcode printed in the preferred range comes out at about 0.011 to 0.013 inch after a 75 percent reduction, at or below the minimum. A 0.75-inch bar becomes about 0.56 inch. Etsy’s own help page warns that a distorted label may not be read by package scanners.

Rotating the label does not help: fitting a sideways 6 x 4 label onto 3 x 5 stock takes a 50 percent reduction.

When 3x5 Makes Sense

  • Labels you design at 3 x 5. Return-address, box-contents, “fragile” or branded labels made in your label software at native size print at full resolution with no scaling.
  • A second roll on the same printer. A 4-inch printer that accepts narrower stock can print both. Rollo lists a 1.57 to 4.1 inch width range for the X1040 and tells users to let the printer re-learn the label whenever they switch size or brand.

If the reason for 3x5 is a small package, change the package instead. USPS says Click-N-Ship labels must be placed fully on the address side and not folded over package edges, so a mailer or box needs a flat face of at least 4 x 6 inches for a standard label.

4x6 vs 3x5 at a Glance

4x6 thermal labels 3x5 thermal labels
Label area 24 sq in 15 sq in
Carrier labels from eBay, Etsy, Shopify, USPS Print at full size Must be scaled to 75%, which can undersize the barcode
Fits a 4-inch printer such as the Rollo X1040 (1.57 to 4.1 in) Yes Yes
Fits a 2.4-inch printer such as the Brother QL-800 No No
Good for Postage and carrier labels Return-address, contents and branded labels designed at 3 x 5

The 2.4-inch row matters if you are deciding on a printer as well: neither size fits a 2-inch-class machine. See 2-inch vs 4-inch label printers .

Sources

FAQ

Can I print a USPS, eBay or Etsy shipping label on a 3x5 label?

Only by shrinking it. None of these platforms lists a 3x5 format, so a 4x6 label has to be scaled to 75 percent (3 x 4.5 inches) to fit. That shrinks the barcode by the same amount and can take it below the 0.013-inch minimum bar width in the USPS Domestic Mail Manual. Use 4x6 stock instead.

My package is too small for a 4x6 label. What should I do?

Use a box or mailer with a flat face of at least 4 x 6 inches. USPS says Click-N-Ship labels must sit fully on the address side and not fold over package edges, so shrinking the label is not the fix.

Can a 4x6 label printer also print 3x5 labels?

Usually, if the printer accepts 3-inch-wide stock. The Rollo X1040, for example, takes labels 1.57 to 4.1 inches wide. Recalibrate when you switch sizes. A 2.4-inch printer such as the Brother QL-800 is too narrow for either size.