How to print a Letter or A4 shipping label on 4×6 thermal paper
A practical guide to cropping PDF label whitespace, preserving barcodes, choosing paper size and troubleshooting tiny or sideways thermal prints.
By PushPDF · Updated
Start with the PDF label
Download the original PDF from the shipping service you used. A Letter or A4 download may put the actual shipping label in one corner and leave the rest blank. Printing that whole page with Fit to paper can make the label too small for a thermal printer. Keep the original download as your backup.
PushPDF prepares a print copy of an existing label. It does not create postage, buy a shipment, edit an address or validate carrier acceptance. Use a current label for the shipment you intend to send. Choose a PDF up to 25 MB and 50 pages; this browser tool does not upload it to the cloud.
Crop whitespace without clipping barcodes
Open Crop PDF and choose the file on your device. Click Auto trim whitespace, then review the blue crop area. The crop should contain the entire label, including addresses, service markings, routing text and every barcode. Keep the white quiet zones around barcodes. Drag a new selection or adjust the numeric margins if the automatic bounds are unsuitable.
Auto trim finds visible marks; it cannot decide which marks a carrier requires. A footer outside the label may make the crop wider than expected. Review the source before excluding it. Cropping is for printing and can retain hidden PDF content; it is not secure redaction.
Choose 4×6 and check orientation
Select 4×6 inches as the output paper size. PushPDF fits the crop proportionally, preserves the original PDF artwork and adds a small output safety margin. Auto orientation matches the crop shape to the paper shape; it does not read the label to determine which way the text should face. Use a manual rotation if the label is upside down.
Generate the print preview and review the result before downloading. If you repeatedly receive the same layout, save a label preset on this device. On the next file, explicitly apply the preset and review the crop again. Only the crop geometry, paper size and rotation are saved, not the document or filename. For a multipage file, apply one crop to all pages only when their layouts match.
Print one label at Actual size
Open the downloaded PDF and select your thermal printer. Choose 4×6-inch paper in the printer settings and Actual size / 100% in the PDF print dialog. Avoid fitting a Letter page again after producing a 4×6 PDF. Paper names and driver controls vary by printer, so confirm the physical stock matches the selected dimensions.
Print one test label first. Check the smallest text and try scanning the barcode before printing a batch. A PDF preview cannot prove physical scan quality: printer resolution, darkness, damaged stock and the original label all matter. If the label is tiny, check the crop and paper size. If it is sideways, adjust rotation. Do not stretch a barcode or trim its white border to make a label fit.