The 100 × 150mm, or 4x6, label is the standard for shipping, but it's not the only size thermal printers handle. Smaller formats like 4x4 and 4x2 exist for jobs that don't need the full shipping-label footprint, and knowing what they're for stops you either wasting a big label on a small job or trying to squeeze a shipping label onto a size that won't fit it.
Why 4x6 is the default
The 100 × 150mm label won because it fits the barcode, both addresses and the postage details for every major UK courier, all on one self-adhesive label. It's the size the carriers designed their systems around, which is why nearly every shipping label you'll ever print is 4x6. Our 4x6 size guide covers how it became the standard.
What 4x4 labels are for
The 4x4, or 100 × 100mm, square label is the common choice for smaller jobs like product labels, asset tags, bin labels and short return labels. It's big enough for a readable barcode and a line or two of text, but smaller and cheaper than a full shipping label. If you print the same small label in volume, 4x4 is often the right size.
What 4x2 and smaller labels are for
4x2, or 100 × 50mm, and smaller formats are for compact labels, price tags, small product labels, cable or shelf labels, anything where the label needs to be unobtrusive. At these sizes, print resolution starts to matter, because a dense barcode on a tiny label needs a finer printhead, which is where 300 DPI comes in.
Can your printer handle multiple sizes?
Most thermal printers accept a range of label widths, as long as they're within the printer's minimum and maximum, and you adjust the guides and the driver's paper size to match. The core size is usually the same 25mm, so swapping between 4x6 and 4x4 is a settings change, not a hardware change. Our roll diameter guide covers the fit side.
When to add a smaller size to your setup
The practical trigger is when you find yourself printing a small label repeatedly and wasting a full 4x6 on it. Product labels, warehouse bin tags and price labels are the usual suspects. If you do enough of those, a smaller label size saves money and looks more professional than a big shipping label doing a small job.
The resolution trade-off at small sizes
As labels shrink, barcodes get smaller and denser, and a 203 DPI printer that's perfect for 4x6 shipping labels may struggle with a tiny, data-dense 4x2 barcode. If small-label printing is a big part of your operation, a 300 DPI printer is worth considering for that work, while keeping your 203 DPI unit for shipping.
Matching size to the job
The rule of thumb is simple: shipping and anything carrier-scanned is 4x6, product and asset labels are 4x4 or 4x2 depending on how much text and barcode they carry, and anything smaller is specialist. Match the label to the job and you'll stop paying for label real estate you don't use.
A note on switching stock
If you run multiple sizes, the main operational cost is the swap, changing rolls and resetting the paper size each time. For most sellers it's not worth the hassle for a handful of small labels, so the honest advice is to standardise on 4x6 until the volume of small labels genuinely justifies a second size.
Frequently asked questions
What's the standard thermal label size? 100 × 150mm, or 4x6, is the shipping standard, and it fits the barcode and addresses for every major UK courier.
When should I use 4x4 labels? For product labels, asset tags and short labels that don't need the full shipping-label size. They're cheaper than 4x6 for repeated small jobs.
Do I need a 300 DPI printer for small labels? Only if you print small, dense barcodes. A 203 DPI printer is fine for 4x6 shipping labels, but small labels benefit from 300 DPI.
The 4x6 labels every dispatch runs on
For shipping, 4x6 is the standard for a reason. Our 100 × 150mm direct thermal labels print every carrier's barcode at full size, every time.
Shop 4×6 Labels