How do I print an A4 PDF as a 100 × 150 mm label?

Have you downloaded an A4 shipping label, but your thermal printer uses 100 × 150 mm labels? The file can be printed correctly, provided you isolate the useful area and maintain the barcode's proportions.

The most important thing is to avoid stretching the PDF. A slightly reduced address often remains legible, but a distorted, cut, or low-contrast barcode can slow down package processing. Here is the reliable method for Windows, Mac, iPhone, and Android.

A4 PDF vs. 100 × 150 mm Label: What's the Difference?

An A4 document measures 210 × 297 mm. A common thermal shipping label measures 100 × 150 mm. The term "4×6 inches" refers to a very similar format, while some platforms also group this choice under the name "A6."

These formats do not have exactly the same dimensions. Therefore, an entire A4 page should not be squashed onto a small label. First, you need to identify the file configuration:

• Native thermal PDF: The page contains only the label, already in 100 × 150 mm or 4×6 format;
• Label placed on an A4 page: The label occupies only part of the sheet and needs to be cropped;
• Label accompanied by a receipt or instructions: Only the area intended for the package should be sent to the thermal printer;
• Multiple labels on one page: Each label must be separated before printing.

The Best Solution: Download the Thermal Format Directly

Before modifying the PDF, go back to the shipping platform and look for one of the following choices:

• Thermal;
• 4×6 inches;
• 100 × 150 mm;
• 10 × 15 cm;
• A6 or label printer.

A file generated directly in the correct format maintains the best sharpness and avoids manual cropping. Shopify notably distinguishes the 4×6 / 100 × 150 mm thermal format from A4 and Letter formats in its official guide for printing shipping documents.

If your platform only offers an A4 PDF, keep the original file: it is still preferable to a screenshot or a photo.

How to Convert an A4 Label to 100 × 150 mm

Step 1: Identify the Area Actually Intended for the Package

Open the PDF and check if the label contains the address, shipping number, carrier references, and all barcodes. Deposit instructions, customer receipts, or preparation slips do not necessarily need to be affixed to the package.

Step 2: Crop Without Distortion

Preferably use the cropping function of the application provided with your printer or a PDF tool. Frame the entire label, without cutting the borders, marks, or numbers below the barcode.

Maintain the original proportions. Never stretch the area solely to fill all four sides of the page.

Step 3: Select 100 × 150 mm Paper

In the printer properties, choose 100 mm width and 150 mm height. Depending on the file orientation, use portrait, landscape mode, or automatic rotation.

Step 4: Check the Preview

Before printing, ensure that no information extends beyond the frame. The barcode must remain straight, high-contrast, and surrounded by a white area.

Recommended Settings

In Adobe Acrobat, the "Actual size" option prints without scaling, while "Fit" adjusts the page to the selected paper. Adobe explains these differences in its documentation on PDF print sizes. Use "Actual size" when the PDF page is already correctly cropped to the thermal format.

Printing an A4 PDF to 100 × 150 mm on Windows

1. Save the original PDF to your Downloads folder.
2. Open it in Adobe Acrobat Reader or the application recommended with the printer.
3. If the page is A4, crop or import only the label area.
4. Open the print window and select the thermal printer.
5. In "Properties" or "Preferences," choose 100 × 150 mm.
6. Select "Actual size" if the resulting document is already 100 × 150 mm.
7. Check the orientation in the preview.
8. Print a single test label.

If the result is tiny in the center of the label, the PDF is probably still considered an A4 page. Go back to the cropping step instead of increasing the print density.

Printing 100 × 150 mm on Mac

1. Create a copy of the PDF to keep the original.
2. Open the copy in Preview.
3. If necessary, use the rectangular selection and cropping tool to keep the entire label.
4. Choose File > Print.
5. Select the thermal printer and 100 × 150 mm format.
6. If this format does not appear, use "Manage Custom Sizes" and create a 100 mm × 150 mm paper size.
7. Set the scale to 100% when the PDF is already in the correct format.
8. Check the preview before running the test.

Apple details how to create a custom format in its guide to paper sizes on Mac.

Printing from an iPhone or Android Smartphone

A Bluetooth thermal printer usually uses its own application to receive and prepare files. The usual method is as follows:

1. Download the PDF from the platform or email;
2. Open the application associated with the printer;
3. Import the PDF with the "Share" or "Open with" command;
4. Activate automatic cropping or manually frame the label;
5. Choose 100 × 150 mm;
6. Correct the rotation if the address appears sideways;
7. Print one copy and check it.

Avoid zooming into the PDF and then taking a screenshot. This method can reduce the definition of small bars. For connection and settings according to your device, consult our Bluetooth iPhone, Android, Mac and Windows guide.

Special Cases Depending on the Platform or Carrier

Menus do not always have the same name. Vinted, Mondial Relay, Colissimo, Chronopost, Amazon, Shopify, and shipping software can provide different layouts.

Apply this order of priority:

1. Download the thermal format offered by the platform;
2. Choose 4×6, 100 × 150 mm, 10 × 15 cm, or A6 depending on the displayed options;
3. If only A4 is available, crop the original PDF;
4. Print to the correct size without distorting the barcode;
5. Check each new label template before batch printing.

To check the appropriate dimension for your use, also read our guide to thermal label formats.

Why Is the Label Printing Incorrectly?

The Label Is Tiny

The complete A4 page has been reduced onto a 100 × 150 mm label. Crop the label area or download the thermal version.

The Barcode Is Cut Off

The wrong format, an excessively large margin, or incorrect orientation is selected. Check the preview and paper properties.

The Text Is Stretched

"Fill page" option has modified the proportions. Revert to the original file and maintain the width/height ratio.

A Blank Label Prints After Each Print

Page length or gap detection between two labels is incorrect. Select 100 × 150 mm then restart printer calibration.

The Print Is Faint or Blurry

Use the original PDF, check the direction of the thermal paper, clean the print head once the device has cooled down, and slightly adjust the density. Our guide Faint, Misaligned, or Blank Thermal Label: 12 Solutions helps you diagnose the problem in the correct order.

Final Check Before Attaching the Label

• The full address is legible;
• All barcodes are visible and clear;
• No edges are cut;
• Barcode lines are neither stretched nor compressed;
• The tracking number appears;
• The label matches the correct package;
• The adhesive is applied to a clean, dry, flat surface.

Do not place shiny tape, creases, or carton joints over the barcode. If you are preparing multiple orders, use a 100 × 150 mm label holder to keep the paper aligned and prevent it from getting jammed behind the printer.

Frequently Asked Questions

Can an A4 PDF be printed directly on a 100 × 150 mm label?

Yes, but not by systematically reducing the entire page. If the label occupies only part of the A4 document, you must first crop the useful area or download a thermal version.

Should I choose "Fit" or "Actual Size"?

Choose "Actual size" when the PDF is already in 100 × 150 mm format. If the document is still A4, crop it before printing. "Fit" may be suitable for some files, but the preview must confirm that the proportions remain correct.

Are 100 × 150 mm, 4×6, and A6 exactly the same?

No. They are often grouped in print menus, but their exact dimensions differ slightly. Prioritize the format requested by the carrier and the one designed for your labels.

What resolution is needed for a shipping label?

A resolution of 203 DPI is generally suitable for standard shipping addresses, QR codes, and barcodes. PDF sharpness, density, label quality, and print head cleanliness also matter.

Can I print from a phone?

Yes, with a Bluetooth printer and a compatible app. Import the original PDF into the app, crop it if necessary, and select 100 × 150 mm.

What equipment should I use to regularly print labels?

A 4×6 direct thermal printer, 100 × 150 mm adhesive labels, and a stable holder make for a simple setup. The Metashopper Bluetooth thermal printer works at 203 DPI up to 150 mm/s and accepts common labels from a smartphone or computer.