LabelFitQuick answer: To convert an A4 shipping label to 6x4, open the label PDF in LabelFit, check the box covers the whole label, choose 100 × 150 mm (or 4 × 6 in) and download the PDF. Print it at Actual size or 100% on your thermal printer. The label is cropped out of the page rather than shrunk with it, so the barcode stays at or near its original size.
How to convert an A4 label to 6x4 in 4 steps
- Get the label PDF. Download the printable label from Vinted, Evri, Royal Mail, eBay, USPS.com or your carrier. Keep it as a PDF if you can; a screenshot works but is less sharp.
- Drop it into LabelFit. LabelFit finds the label on each page. It leaves out instructions and cut lines, and marks packing slips and customs forms as separate pieces.
- Check the preview. Green ticks mean nothing is cut off and the label isn't shrunk too much. If a box is wrong, drag it or its corners, or tap it to change what it is.
- Download and print at 100%. Download the PDF for a desktop printer, or save the image for a phone printer app. Print with the paper size set to 4 × 6 in or 100 × 150 mm and the scale at Actual size or 100%.
Why “Fit to page” ruins A4 labels on a thermal printer
An A4 page is 210 × 297 mm and a 6x4 label is about 100 × 150 mm. If you send the whole A4 page to a 6x4 printer with Fit to page, it shrinks everything, label and blank paper alike, to about 48% (100 ÷ 210). A label that was already 6x4 on the sheet comes out roughly half size, with bars so thin that many scanners struggle. A US letter page shrinks to about 47%.
LabelFit crops the label first and then fits only the label to your roll, so a 6x4 label on an A4 sheet prints at around 95–100% instead of 48%. The preview shows the exact percentage before you print.
Label and paper sizes
| Size | Millimetres | Inches | Typical use |
|---|---|---|---|
| 4 × 6 in (“6x4”) | 101.6 × 152.4 | 4 × 6 | US thermal shipping labels |
| 100 × 150 mm | 100 × 150 | 3.94 × 5.91 | UK and EU thermal rolls sold as 6x4 |
| A6 | 105 × 148 | 4.13 × 5.83 | A quarter of an A4 sheet |
| Half sheet | 139.7 × 215.9 | 5.5 × 8.5 | Two-per-sheet label paper for ordinary printers |
| A4 | 210 × 297 | 8.27 × 11.69 | UK and EU home printer paper |
| US Letter | 215.9 × 279.4 | 8.5 × 11 | US home printer paper |
LabelFit can also print to A6, 4 × 4 in, a 62 mm continuous roll, any custom size, or two labels per Letter or A4 sheet for half-sheet sticker paper.
Which labels does it work with?
Any label that comes as a PDF or an image. Presets set the usual paper size for each source; the label itself is still found automatically, because layouts change.
| Where the label comes from | What you usually get | Guide |
|---|---|---|
| Vinted (Evri, InPost, Royal Mail, DPD) | An A4 PDF with the label on part of the page | Vinted guide |
| Evri | A4 from marketplaces; Evri's own site also offers a 4 × 6 label | Evri guide |
| Royal Mail Click & Drop | A4 with 1, 2 or 4 labels, or a native 6x4 label | Royal Mail guide |
| USPS.com Click-N-Ship | An 8.5 × 11 in page with the label in the top half | USPS guide |
| eBay (US half-sheet, UK A4) | Label across the top half of a letter page, or in a corner of an A4 page | eBay guide |
| Mercari | An 8.5 × 11 in page, unless you pick 4 × 6 in Mercari's label settings | Use the Mercari preset |
| Anything else | Any PDF, PNG or JPG with a label on it | Auto-detect |
Print settings that keep the barcode sharp
| Where you print from | Settings |
|---|---|
| Adobe Acrobat Reader | Page Sizing & Handling: Actual size. Paper size 4 × 6 in or 100 × 150 mm in the printer properties. |
| Chrome or Edge PDF viewer | Paper size 4 × 6 in or 100 × 150 mm. Scale Default or 100, not Fit to printable area. |
| Preview on a Mac | Paper Size: your 4 × 6 in or 100 × 150 mm custom size. Scale 100%. |
| Phone printer app | Choose Image here, 203 dpi for most printers or 300 dpi for 300 dpi models. Set the same label size in the app and turn off extra scaling. |
The tool has a step-by-step version of these settings under Print settings for a perfect 100% print, with a button to copy them.
Packing slips, customs forms and multi-label sheets
- Label and packing slip on one page: LabelFit marks the slip separately. Leave it out, or print it on its own 6x4 page. See how to split a label and packing slip.
- CN22 and CN23 customs forms: printed on their own page by default, so they don't get left behind.
- A4 sheets with 2 or 4 labels: every label becomes its own page, in reading order.
- Lots of orders: drop several PDFs at once and print them all from one file.
- A layout auto-detect gets wrong: fix the box once, save it as a layout, and LabelFit reuses it for every file from that source. Layouts can be exported and imported as a file.
Private by design: nothing is uploaded
Shipping labels carry your buyer's name and home address. LabelFit reads the PDF with pdf.js inside your browser tab and writes the new PDF with pdf-lib, also in the tab. There's no upload step and no server that could keep a copy. After your first conversion, LabelFit keeps working offline, so you can switch on airplane mode and see for yourself that nothing needs the internet.
Printing from a phone
Bluetooth label printers print from their own app, and many apps handle images better than A4 PDFs. Choose Image, pick 203 or 300 dpi and tap Share to printer app: the image is exactly label-sized. See the phone printing guide for iPhone and Android steps.
Step-by-step guides
Frequently asked questions
Is LabelFit really free?
Yes. Every feature is free: any number of labels, batch conversion, packing-slip splitting, saved layouts and phone images. There's no account and nothing is added to your labels.
Are my labels uploaded anywhere?
No. The PDF is opened and converted inside your browser tab, so your buyers' names and addresses never leave your device. After your first conversion LabelFit also works offline.
Will the barcode still scan after converting?
LabelFit copies the label into the new PDF as vector graphics, so bars and text stay as sharp as in the original. It shows the print scale for every label and warns you if a label would be shrunk below 80%. Print one test label and check the barcode is crisp and nothing is cut off.
Should I choose 4 × 6 in or 100 × 150 mm?
Pick the size printed on your label roll and set your printer to the same size. UK and EU “6x4” rolls are usually 100 × 150 mm; US rolls are 4 × 6 in (101.6 × 152.4 mm). The two differ by less than 2.5 mm, so either works as long as the PDF and the printer setting match.
Why does my label print tiny or in a corner?
Usually the printer is still set to A4 or Letter paper, or the print dialog is set to Fit to page, which shrinks the whole sheet. Convert the label to 6x4 here, set the paper size to 4 × 6 in or 100 × 150 mm, and print at Actual size or 100%.
Can I convert several labels at once?
Yes. Drop several PDFs, a multi-page PDF or an A4 sheet with 2 or 4 labels. Every label becomes its own 6x4 page in one PDF, or one image each in a ZIP when you choose Image.
Does LabelFit change anything on the label?
No. It only crops, rotates and scales. Nothing is ever printed on a shipping label or customs form. If you choose to keep a packing slip, that page gets a small “Made with LabelFit” line under the slip.
Which printers does it work with?
Any printer that takes 4 × 6 in or 100 × 150 mm labels: desktop thermal label printers such as Rollo, Munbyn, Zebra or iDPRT models, Bluetooth label printers that print from a phone app, and ordinary printers with half-sheet label paper (use the 2-per-sheet sizes).
Last updated · Written by the MiniTools team. Print a test label before shipping a batch.