How the labels remaining calculation works
The calculator first estimates the remaining web length from the area of the wound roll and the effective material thickness. It then divides the web length by the repeat pitch. If your roll has more than one label across the web, the repeat count is multiplied by that number of columns.
Pitch = label length + gap
Estimated labels = floor(web length ÷ pitch) × labels across
What thickness should you enter?
Use the combined caliper of the facestock, adhesive and release liner—not just the face material. A small error in thickness can noticeably change the estimated quantity on a large roll. If you only know the manufacturer's nominal stock thickness, treat the result as an estimate rather than an inventory count.
Why the physical count may differ
Real rolls are not perfect mathematical cylinders. Compression, winding tension, air between layers, splices, missing labels, liner thickness variation and imperfect OD measurements all affect the result. For production-critical purchasing or reconciliation, verify a sample roll against an actual count and adjust the effective caliper if needed.
Worked example
A roll with a 150 mm current OD, 76 mm core OD, 160 µm total material thickness, 100 mm label length and 3 mm gap has a 103 mm pitch. The calculator converts all inputs to one internal unit before applying the roll-geometry formula, so mixed mm/inch/micron inputs are safe.