LabelFitQuick answer: If 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%. If your print options include a 4 × 6 label, you can pick that and skip converting.
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.
Related free tools
- FNSKU label generator: Amazon FBA prep labels on the same thermal printer.
- Free invoice generator: add an invoice or receipt to your orders.
Frequently asked questions
Can USPS.com print 4x6 labels directly?
It depends on the print options USPS.com shows you, and they have changed over time. Printer makers such as Arkscan describe Click-N-Ship labels as 8.5 × 11 in pages, which is why many sellers crop them for 4 × 6 thermal printers. If you see a 4 × 6 label option when printing, use it; otherwise convert the letter-size PDF here.
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 Rooh Sites team.