Shipping label prints too small on Mac: why, and how to fix it

You send a shipping label to your thermal printer and get back a postage-stamp version of it, floating in the corner of the roll with white space around it. The barcode is too small to scan. Nothing in the print dialog seems to make it bigger.

Almost always the cause is that the PDF is a full A4 or Letter page with the label occupying only one corner. Your printer is not shrinking the label. It is shrinking the whole page down to fit a 4x6 roll, and the label shrinks with it.

How to tell which problem you have

Open the PDF in Preview and press Cmd+I to show the inspector. Look at the page size.

• 210 × 297 mm, or 8.5 × 11 in — the page is A4 or Letter. This is the common case, and no print setting fixes it. Skip to the cropping section.
• 100 × 150 mm, or 4 × 6 in — the page is already the right size, so this is a print-dialog problem. The next section is yours.

Fix 1: the page is already 4x6 but still prints small

Two settings shrink a correctly sized label, and they compound. In the macOS print dialog:

1. Set Paper Size to your 4x6 media. If it is not listed, choose Manage Custom Sizes, add one at 100 × 150 mm with all four margins set to 0, and pick it.
2. Set Scale to 100%, or turn off Scale to Fit. Fit-to-page adds a printable-area margin the label does not need.

Non-zero margins in a custom paper size are the part people miss. macOS treats them as unprintable and scales your artwork down to clear them, which produces exactly the shrunken label with a white border.

Fix 2: the label is in the corner of an A4 page

Here the only real fix is to cut the label out of the page before printing, so the printer receives a 4x6 document instead of an A4 one. Preview does this for free:

1. Open the PDF in Preview.
2. Show the markup toolbar, then drag a rectangular selection around the label.
3. Press Cmd+K to crop.
4. Print with paper size set to 4x6 and scale at 100%, as above.

This is genuinely fine for a few orders a day. The catch is that it is the same six actions every single time, the selection is freehand so every label lands slightly differently, and it does not batch. At fifty orders it stops being a workaround and starts being the job.

Fix 3: let something measure it once

The useful observation is that a given carrier and integration always put the label in the same place. Your marketplace generates the same geometry every time. So the crop only needs working out once, and after that it can be applied automatically.

For a single file, our free browser tool does exactly this: it finds the label on the page, crops it out at full size rather than scaling it down, and never uploads anything.

There is a reason it measures rather than asks. Carrier-specific geometry tables do not work: the same InPost or DHL account produces a native A6 through the carrier's own manager and an A6 pasted into an A4 corner through a marketplace. Nobody holds that table. Only the person with the file in front of them knows, so the file is what gets measured.

What about the printer driver?

Worth ruling out, but rarely the culprit. Rollo, MUNBYN, Xprinter, Brother and Dymo units generally show up on macOS over USB without a vendor driver. If the printer prints at all, it is working, and a label that comes out small is a page-size problem rather than a driver one.

The one driver-adjacent thing worth checking is that the printer's default paper size is not still set to Letter. macOS remembers that per printer and applies it whenever a document does not specify otherwise.