Our 4×6 label size guide covers why 100 × 150mm is the standard for UK parcel shipping. It isn't the only size worth knowing about — other formats exist for specific, legitimate reasons outside standard courier dispatch.
Why 4×6 dominates (a quick recap)
100 × 150mm balances enough space for a barcode, QR code and address block against a compact roll size for high-volume printing, and every major UK courier's label layout is built around it by default. For parcel shipping specifically, there's rarely a reason to deviate.
Smaller formats for product and asset labels
Product barcode labels, price tags and asset tags are typically much smaller — commonly in the 25 × 50mm to 50 × 25mm range — since they only need to hold a single barcode and short text rather than a full shipping layout. These are usually printed on a different label stock and, often, thermal transfer rather than direct thermal, given their longer intended lifespan; see our direct thermal vs thermal transfer guide for why that distinction matters more for durability-focused labels.
A6 and A5 for document-style labels
Some businesses use A6 (105 × 148mm, close to but distinct from 4×6) or A5 (148 × 210mm) formats for labels that double as packing slips or need to carry more printed information than a standard shipping label layout allows — commonly in B2B contexts where a delivery note travels with the parcel. This is a genuine use case, but worth confirming your printer and courier software both support the non-standard size before committing to it.
Larger formats for pallet and freight labelling
Bulk freight and pallet labelling sometimes uses larger formats (4×8" or bigger) to accommodate additional handling instructions, hazard markings, or multiple barcodes required for pallet-level logistics — a different world from parcel-level dispatch, with different printers built to handle the larger format.
Matching size to actual use case
The rule of thumb: if it's a parcel going through a UK courier network, 100 × 150mm is right almost without exception. If it's a product label, asset tag, or a document-style label carrying more information than a barcode and address, that's when it's worth deviating — and worth confirming your specific printer and software combination genuinely supports the size before ordering stock, covered in our thermal printer buying guide.
The size that matters for shipping
For UK parcel dispatch, 100 × 150mm is the format that works everywhere — which is the only size we sell.
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