101.6 x 152.4 mm. That is 4 x 6 inches converted exactly, and it is the size every SMKlog label prints at and the size US carriers build their label templates around. The number that trips people up is not that conversion; it is the 100 x 150 mm rolls sold by printer makers, which round it off.
4 x 6 in and 101.6 x 152.4 mm describe the identical rectangle. What differs is what gets sold next to it.
Every figure below is exact inch-to-millimeter math (1 in = 25.4 mm), not a marketing round number. The 4 x 6 row is the one that matters for buying a label from SMKlog or any US parcel carrier.
| Format | Inches | Millimeters (exact) | Where it shows up |
|---|---|---|---|
| Parcel label | 4 × 6 in | 101.6 × 152.4 mm | Standard SMKlog label and the format nearly every US carrier's label PDF is built for |
| Half sheet | 8.5 × 5.5 in | 215.9 × 139.7 mm | Two labels printed per US Letter sheet, then cut apart |
| US Letter | 8.5 × 11 in | 215.9 × 279.4 mm | The plain paper a 4 x 6 PDF prints onto before trimming |
| Small parcel label | 2 × 1 in | 50.8 × 25.4 mm | Barcode stickers used for bin or item labeling, not postage |
A label is a printed rectangle, not a shipping input. It carries no weight and no dimensions of its own, so nothing on this page changes what a parcel costs to send. That number comes from the box, and the calculator prices your box specifically.
Thermal label rolls are almost always sold as "100mm x 150mm," a rounded figure. The true conversion is 101.6 x 152.4 mm, so a roll cut to the rounded number runs 1.6 mm narrow and 2.4 mm short against a US carrier's 4 x 6 in template. Most printers absorb that in the margin; a printer with tight edge calibration can crop the bottom of the barcode instead.
ISO A6 is 105 x 148 mm, a different aspect ratio from 101.6 x 152.4 mm. A label PDF sent to an A6 tray either stretches to fill the page, distorting the barcode, or gets letterboxed with a blank strip, depending on the print driver's scaling setting.
Set the print driver to "actual size" or "100%" rather than "fit to page," and confirm the paper size selected in the driver matches the stock loaded, whether that is a true 4 x 6 in / 101.6 x 152.4 mm die-cut or a 100 x 150 mm roll. Scaling in software is what turns a 1.6 mm rounding gap into a cropped barcode.
101.6 x 152.4 mm. That is the exact metric conversion of 4 x 6 inches, which is the working standard for parcel labels at SMKlog and every major US carrier.
Because 100 x 150 mm is a rounded metric size sold as an approximate match for 4 x 6 in, not the same dimension. The gap is 1.6 mm on one side and 2.4 mm on the other, small enough that most printers absorb it in the margin but large enough to crop a barcode on a printer calibrated tightly to the roll.
No. A6 is 105 x 148 mm under the ISO 216 paper standard, a different aspect ratio from a 101.6 x 152.4 mm label. Printing a label PDF at A6 stretches or letterboxes it rather than reproducing it at size.
A US Letter sheet is 215.9 x 279.4 mm (8.5 x 11 in). A 4 x 6 in label printed on it and trimmed still comes out at 101.6 x 152.4 mm; the extra paper around it is waste, not part of the label.
No. The label is a printed sheet of paper or thermal stock; it carries no weight or dimensions of its own and plays no part in a parcel rate. What decides price is the packed box going in the mail, priced through the calculator.