What do the 8, 10, 12 and 15 mm diameters change?

Short answer: The four standard diameters — 8, 10, 12 and 15 mm — differ by roughly three and a half times in material between the smallest and the largest. They are not four sizes of the same product. They cover four different acne situations, and the cost difference between them follows area, not diameter.

What each diameter covers

The material is 0.25 mm hydrocolloid across all four, so the only variable is how much of it a single patch uses. A 15 mm patch carries about three and a half times the material of an 8 mm patch — that ratio is geometry, before any waste.

Cost follows area, not diameter

Doubling the diameter quadruples the area. Going from 8 to 15 mm is a 1.9× increase in diameter and a 3.5× increase in material, which is why a size upgrade is never a small line item in a quote. The cost curve is steep at the top end and flat at the bottom:

The other half of the cost is what the size does to the pack. A 15 mm patch fills more of a pouch and needs a larger die-cut sheet area, so the sheet yields fewer patches and the pack count for the same pouch drops. Size and pack count are one decision, not two — which is why the two should be quoted together.

Choosing for a first SKU

For a first private label run, the usual starting point is a mixed pack of 8 mm and 12 mm: the small size for daytime and visible placement, the larger for overnight. It covers most of the use cases a customer describes, and it does not require a third die.

Two situations argue for a different choice. If the patch carries print or a character, go up: a face or a logo needs surface to read, and 8 mm is too small to hold detail. If the product is aimed at body use rather than the face, 15 mm is the working size and the pack count should be planned around it from the start.

What does not work is treating the sizes as interchangeable in a quote. A price per patch without a diameter is not a comparable number — 1,000 patches at 8 mm and 1,000 at 15 mm are different amounts of material, different die, and different packing.

One question worth settling early

Ask whether the diameter is the finished patch or the printable area inside it. On a shaped patch the two differ, and on a circle they are the same. Getting this wrong by a millimetre shows up in the pack count, not in the sample, which is why it tends to surface late.