LabelFitQuick answer: USPS.com Click-N-Ship gives you the label on a letter-size (8.5 × 11 in) page, with the label in the upper part and receipt details and instructions below. Open that PDF here: LabelFit crops the label, turns it upright and makes a 4 × 6 in PDF. Print it on your thermal printer at Actual size or 100%.
How to print a USPS.com label on 4x6 thermal labels
- Save the label PDF. After buying postage on USPS.com, save the 8.5 × 11 in label PDF instead of printing it.
- Open it above. The USPS.com letter preset sets 4 × 6 in paper and finds the label in the top part of the page.
- Check the preview. The label should be upright on the 4 × 6 page. If it's the wrong way round, select the box and use Rotate.
- Print at Actual size. Paper size 4 × 6 in, scale 100% or Actual size, portrait.
What happens to the rest of the page
The lower part of a USPS.com label page usually holds the label receipt and instructions, separated from the label by a cut line. LabelFit ignores the cut line and leaves the receipt and instructions out, shown as a grey dashed box. If you want the receipt on its own 4 × 6 page too, tap that box and choose Packing slip (own page).
Why not print the letter page with “Fit to page”?
| Method | Size of the printed label |
|---|---|
| Whole 8.5 × 11 page fitted onto 4 × 6 | About 47% of the original, so the barcode bars are less than half as wide |
| Label cropped with LabelFit, Fit | Usually 90–100%, shown in the preview |
| Label cropped with LabelFit, Actual size | Exactly 100%, if the label fits on 4 × 6 |
Shippo's printing guidance notes that USPS has said poor print quality or barcodes near package edges or creases can get a parcel flagged. A full-size, sharp barcode stuck flat on the box avoids that.
Thermal printer setup for 4x6
Install your printer's driver and set its default paper size to 4 × 6 in. On a Mac, if 4 × 6 isn't listed, add it in the print dialog under Manage Custom Sizes. Then print the LabelFit PDF at 100%. Desktop thermal printers sold for shipping, such as Rollo, Munbyn, iDPRT or Zebra models, all take 4 × 6 in labels.
Other shipping sites
Some shipping platforms can produce 4 × 6 labels directly; check their label settings first. For any service that only gives you a letter-size PDF, this converter works the same way. For eBay's half-sheet labels see the eBay half-sheet guide.
Frequently asked questions
Can USPS.com print 4x6 labels directly?
Not usually. Printer makers such as Arkscan note that USPS.com Click-N-Ship produces labels for 8.5 × 11 in paper, which is why a cropping step is needed for 4 × 6 thermal printers.
Is it OK to ship with a USPS label printed on a thermal printer?
Yes, 4 × 6 thermal labels are widely used for USPS shipping. What matters is a clear, unsmudged barcode that isn't folded over an edge or covered by shiny tape.
Will the label be rotated correctly?
LabelFit turns a landscape label 90° so it fills the portrait 4 × 6 page. You can rotate it the other way or 180° with the Rotate buttons.
Does it work with Mercari or other letter-size labels?
Yes. Use the Mercari letter preset, or Auto-detect for any other 8.5 × 11 in label PDF.
More label guides
Last updated · Written by the MiniTools team.