troubleshooting guide
Fix label printed on wrong paper size (4×6 vs letter/a4) — what is actually risky?. Check scale, paper size, margins, orientation and barcode whitespace before reprinting.
Best next step
Start with the tool or template that matches this guide before printing paid postage again.
Last reviewed: 2026-06-15
Separate the source page size from the paper you accidentally used. If the label content stayed at its original scale and is complete, move it to the correct workflow; if the barcode or required text was resized or cropped, reprint from the original PDF with matching 4 × 6, Letter or A4 media.
Symptom-led fix
Follow the symptom that best matches your bad print. Each step points to the safest next tool before you buy postage again.
A full Letter or A4 page is being fitted onto one 4×6 thermal label.
Inspect the PDF page box. Get the issuer's 4×6 format or extract only a complete label area; do not enlarge the miniature output.
Inspect the PDF pageA true 4×6 source prints proportionally smaller on matching 4×6 media.
Confirm 4×6 in the driver, disable Fit, print one blank template, then calculate a correction only if the media path already matches.
Measure the scale errorThe label boundary is correct, but fine lines are fuzzy, gray or broken.
Treat this as print quality, not page scale. Test density, speed, media and printhead condition before another live label.
Run a print-quality testCheck whether the PDF page itself is 4×6, Letter or A4. Do not infer the source from the sheet that came out of the printer: a 4×6 label can appear on a larger sheet, and a full sheet can be squeezed onto a thermal roll.
If the complete label remained actual size on extra paper, the problem is mostly paper handling. If every element became smaller, an auto-fit setting changed scale. If one edge disappeared, paper size, orientation, margins or printable area caused a crop.
For a true 4×6 source, use matching thermal media or place it unchanged on a desktop sheet. For Letter/A4 sources, use the matching desktop paper or extract a verified 4×6 label area without shrinking active content.
A readable address does not prove that barcode scale and routing marks survived. Reprint whenever active content changed, and check the issuing carrier or platform when the original format or acceptance requirement is uncertain.
This page is a practical print-setting checklist, not official carrier policy or a promise that a label will be accepted.
Confirm the current format in your platform or carrier account, keep the original PDF, and stop if a test print is cropped, blurred or incorrectly scaled.
Troubleshooting advice is general. Record the printer model, paper size, PDF viewer and scale setting so you can verify each change.
Not necessarily. The important question is whether every active label element stayed complete and at its intended scale; this page cannot certify carrier acceptance.
Compare the printed boundary with the source page size or a ruler template. Uniform shrink usually points to Fit to Page or a media mismatch.
A 4×6 label can sit unchanged on a larger sheet. Do not enlarge it to fill the sheet or cut into active content.
Only when a true label area can be extracted without resizing barcode and routing content. Do not squeeze the entire sheet onto one roll label.
Any resized, cropped, blurred, folded or missing barcode, address, service text, tracking number or quiet zone.
Understand barcode risk before drop-off.
Check seven scan-critical items before handoff.
Avoid repairs that damage barcode scanning.
Check paper, scale and orientation before printing.
Download a blank 4×6 shipping label template.
Fix tiny labels, scaling problems and bad print settings.