Which shipping label size fits your template, how 100x150 mm compares with 4x6 inches, when to choose eco or top-coated thermal, which core suits your printer and how to set paper size and the gap sensor: a practical guide for shippers.
A shipping label is the ID card a parcel carries from the warehouse to the recipient: the delivery address, the shipment barcode and the tracking number are all read from this small surface. Carrier and marketplace systems generate it in two main sizes: 100×150 mm and 100×100 mm. This guide explains the difference between the two, why shipping barcode labels are almost always direct thermal, how to choose between eco and top-coated thermal stock, and which printer settings give you a clean, scannable print.
Shipping label sizes: when to use 100x150 and 100x100
A shipping label holds the recipient and sender details, one or more barcodes, and sometimes a QR code and an order note. All of that has to fit at a scannable size, which takes a generous surface. That is why most carrier and e-commerce integrations output their label template at 100×150 mm. The 100×100 mm format is used for shorter templates, small boxes and additional information labels.
The most reliable way to decide is to check the output setting of the panel or integration you use. If the template is 100×150 mm, your label should be 100×150 mm too. Scaling a 100x150 shipping label to a different size shrinks the barcode and increases the risk of scan failures.
| Feature | 100×150 mm | 100×100 mm |
|---|---|---|
| Typical use | Standard parcel and shipping label | Short templates, small boxes, extra information labels |
| Printable area | Room for address, several barcodes and notes | Enough for one barcode and a short address block |
| Suitable packaging | Medium and large cartons | Small boxes and mailer bags |
| Inch equivalent | Close to 4×6 inch | Close to 4×4 inch |
| Recommended material | Direct thermal (eco or top-coated) | Direct thermal (eco or top-coated) |
Is a 100×150 mm label the same as a 4x6 shipping label?
Almost. 4×6 inches equals 101.6 × 152.4 mm, so a 100×150 mm label is a few millimetres smaller. International software usually defines templates in inches, while many local systems use millimetres. When a 100×150 mm label is printed with a 4×6 inch template, you may see a slight overflow or shift at the edges; if the barcode sits very close to the edge, its last bars can be cut off.
So define the label size in your driver using the real dimensions of the roll in your printer, and keep a few millimetres of safe margin in the layout. If you ship internationally and work with a 4×6 inch template, confirm the exact cut size before you order.
Why are shipping barcode labels direct thermal?
On a direct thermal label, the image forms on a heat-sensitive coating when the print head heats it; no ribbon is needed. For shipping labels, the benefits are clear:
- No ribbon: no extra consumable and no downtime for ribbon changes.
- Fast and simple: during peak dispatch hours the printer runs on the label roll alone, so the only thing operators watch is when a roll runs out.
- Made for short-lived jobs: a shipping label only has to last until delivery; it does not need to stay readable for years.
- Economical: it keeps total cost down for high-volume, single-use printing.
The weak point of direct thermal is its sensitivity to heat, sunlight and abrasion. If you need a product label, an asset tag or anything that must stay legible for a long time, thermal transfer printing on coated paper with a ribbon is the better fit. For shipping labels this sensitivity is rarely a problem, and for tougher journeys the material choice in the next section gives enough protection.
Eco thermal or top-coated thermal?
Once the size is settled, the next decision is the material. Both options are direct thermal; the difference is the protective layer on the surface.
Eco thermal
An economical thermal paper without a protective top layer. It is usually sufficient for standard e-commerce parcels that travel in dry conditions and are delivered quickly. Because it is sensitive to moisture, grease and heavy abrasion, the barcode is more likely to fade on long journeys.
Top-coated thermal
Here a protective coating sits on top of the thermal surface, giving better resistance to moisture, abrasion and handling. It is the safer choice for cold chain shipments, food cartons, parcels handled many times at sorting hubs and long-distance logistics.
Ask yourself: will the parcel wait in a cold store or a humid area? Do cartons rub against each other on conveyors? Does delivery take more than a few days? If any answer is yes, choose top-coated thermal. For exact resistance limits, check the material's technical data sheet and test a sample under your own conditions.
Do not forget the adhesive: an adhesive grade that grips corrugated board well keeps the label, and its barcode, on the box all the way. If you label plastic mailers or other surfaces, mention it before ordering.
Core size and printer compatibility: 40 mm or 76 mm?
The core is the cardboard tube the labels are wound on, and its inner diameter must match your printer. As a rule of thumb:
- 40 mm core: for desktop barcode printers. The roll diameter is limited so it fits under the printer cover; a good match for small and medium shipping volumes.
- 76 mm core: for industrial printers and high-volume warehouses. Larger rolls mean fewer roll changes.
Outer roll diameter, winding direction (labels facing out or in) and labels per roll also depend on the printer. We produce sizes, cores and winding directions compatible with common barcode printers such as Zebra, TSC, Argox and Godex; share your printer model and we will help you pick the right roll. If you are buying a new printer, factor in your daily parcel volume and how often you want to change rolls.
Printer driver settings: paper size and gap sensor
Even with the right label, missing settings cause shifted prints, skipped labels or a blank label after every print. When you load a new roll, follow these steps:
- Define the paper size: create a new label size in the driver with a width of 100 mm and a height of 150 mm (or 100 mm). Select the same size when printing a PDF and turn off scaling options such as fit to page.
- Select the print method: set the media type to direct thermal; if thermal transfer stays selected, the printer may wait for a ribbon and show an error.
- Set the sensor type: use the gap sensor for rolls with spaces between labels, and the black mark sensor for rolls with a printed mark on the back.
- Calibrate: run the printer's automatic calibration after changing rolls so it learns the label length and gap again.
- Balance heat and speed: if the barcode looks faint, increase darkness step by step; too much heat thickens the bars and makes scanning harder.
- Print a test label: scan the first label with a handheld scanner; if it reads cleanly, start the batch.
Frequently asked questions
Should I buy 100×150 mm or 100×100 mm shipping labels?
Buy the size your panel or integration outputs. Most standard shipping labels are 100×150 mm; 100×100 mm is for shorter templates and small parcels. If you are unsure, check the page size of a label PDF.
Do shipping labels need a ribbon?
No. Shipping barcode labels are usually direct thermal and print without a ribbon. Even if your printer supports thermal transfer, you do not need a ribbon for shipping labels; just select direct thermal as the print method in the driver.
Why does the label shift or print a blank label every time?
The most common causes are a paper size in the driver that does not match the roll, or the wrong sensor setting. Define the label size with its real dimensions, select the gap sensor and calibrate the printer.
Can I order a single roll of shipping labels?
In sizes we have in stock, you can order even a single roll and we can ship it the same day. Please confirm stock availability of 100×150 or 100×100 before ordering; a size that is not in stock is made to order in 3–5 business days.
Conclusion: three decisions for the right shipping label
Choosing a shipping label comes down to three decisions: the size that matches your template (usually 100×150 mm, or 100×100 mm for shorter templates), a material suited to the parcel's journey (eco thermal for short, dry deliveries; top-coated thermal for moisture, cold chain and long routes) and a core that fits your printer. Correct driver settings and a test print take care of the rest.
Since 1999 we have printed, die-cut and rewound labels in our own facility in Pendik, Istanbul. Browse our blank thermal labels, get an instant price by size and quantity, or contact us with your printer model. Rolls in stock ship the same day.