You load a fresh sheet of labels, hit print, and everything sits three millimetres too low. One sheet wasted. You nudge something, try again, waste another. Label stock isn't cheap, and this failure mode is maddening because the template looked perfect on screen.
Here are the actual causes, in the order worth checking. The first one accounts for the large majority of cases.
By far the most common cause. Most PDF viewers and browsers default to "Fit to page" or "Shrink oversized pages." Either one resizes your document by a percent or two to leave a safety margin. And that's fatal for labels, because it shrinks the entire grid uniformly. The first label still looks nearly right; by the bottom of the sheet the drift has accumulated into an obvious misalignment.
The fix: in the print dialog, find the scaling option and set it to 100%, Actual size, or None. Not "Fit". If you only change one thing, change this.
A quick way to tell scaling is your problem: if the misalignment gets progressively worse further down the page rather than being constant, it's almost certainly scaling.
If the offset is constant, every label off by the same amount in the same direction. That's your printer's paper handling, not the template. Printers grip and feed paper with a small mechanical tolerance, and some are consistently a millimetre or two off. This is normal and it doesn't mean anything is broken.
The fix: a calibration offset. Print one page on plain paper, hold it against an actual label sheet up to a window or light, and see which way it's off and by how much. Then shift the whole layout by that amount. A good label tool exposes this as a simple nudge control; you set it once for your printer and forget it.
Label product numbers are a maze. Many different numbers share identical geometry. 5160, 5260, 8160, 8460 and others are all the same 30-per-sheet layout, differing only in finish, adhesive, or box quantity. But some numbers that look adjacent are completely different sizes.
The fix: check the physical dimensions printed on the box, not just the product number. If the box says 2⅝" × 1" and 30 per sheet, any template with those exact dimensions works regardless of what number is on it.
A US Letter template printed on A4 paper (or the reverse) will always be wrong, because the sheets are different sizes. A4 is narrower and taller than Letter. If you're in the UK, Europe, or most of the world, your sheets are A4 and you want an A4 layout. The L7160 family rather than the 5160 family.
Before printing any batch onto real stock:
Two sheets of plain paper, versus discovering the problem thirty labels into a sheet of stock.
Our label maker includes an alignment test sheet and a calibration nudge. Set it once for your printer.
Try the Label Sheet Maker