How to calculate shrink sleeve size
A shrink sleeve is printed as a flat tube slightly larger than your container, slipped over it, and shrunk with heat until it grips. So sizing comes down to two numbers: the layflat width (the flat tube measured across, which must clear the widest point the sleeve passes over) and the cut height (how tall the sleeve is cut, with an allowance so it still covers your target after shrinking).
Layflat width is half the widest circumference plus a small slip clearance: (π × max diameter) ÷ 2 + about 3 mm. The seam overlap and glue area are added to the print and slit width (twice the layflat plus about 1 mm and 7 mm), not to the layflat, so they never loosen the sleeve. Cut length is your coverage height plus the film’s vertical (machine-direction) shrink — commonly around 2% — plus a little press snap-back. The one thing static charts miss is whether the film can actually shrink enough — a sleeve going over a wide cap onto a narrow neck needs high-shrink film, which is why this tool also checks the required shrink against the film’s maximum.
Film choice drives how much it can grip
| Film | Typical max shrink | Notes |
|---|---|---|
| PETG | ~55% standard, up to ~78% high-shrink | Highest shrink and most common. Standard PETG hurts PET bottle recycling: it softens and clumps PET flake in the recycler’s dryer and its inks can tint the flake. Perforate it for removal, or ask for one of the two options below |
| Crystallizable PET (cPET) | up to ~75% | Recognized by the Association of Plastic Recyclers (APR) as compatible with PET bottle recycling when printed with washable inks |
| Floatable polyolefin | Lower than PETG; check the data sheet | Floats away from PET flake in sink-float separation; APR has recognized a floating polyolefin sleeve for PET bottles |
| PVC | ~55–65% | Inexpensive, but complicates PET bottle recycling |
| OPS | ~65% | Lower density, softer feel |
| PLA | ~40–70% by grade | Bio-based; process window is narrower |
These are typical maximums — confirm the exact shrink curve with your converter, because it drives whether the sleeve hugs complex contours without wrinkling. For the format decision itself, see shrink sleeve vs pressure-sensitive labels.
Questions
How do I calculate shrink sleeve size?
Layflat width is half the widest circumference the sleeve passes over plus a slip clearance of about 3 mm: (pi times max diameter) divided by 2, plus clearance. Print width is twice the layflat plus about 1 mm for the seam, and slit width twice the layflat plus about 7 mm for the glue area. Cut length is your coverage height plus the film’s vertical shrink, commonly about 2%, plus a little press snap-back. The calculator above computes all of these and checks whether your film shrinks enough to grip the narrowest diameter.
What is layflat width on a shrink sleeve?
Layflat width is the flat printed tube measured across when pressed flat. Doubling it gives the tube circumference. It must be large enough to slip over the widest part of the container before shrinking, so it is calculated from the maximum diameter, not the average.
Why does my shrink sleeve wrinkle or not grip?
Usually the film cannot shrink enough for the diameter change it has to cover. Going from a wide cap to a narrow neck can require more shrink than the film provides, causing loose spots or wrinkles. Either use a higher-shrink film such as PETG or reduce the diameter variation the sleeve must span.
How much bigger than the container should a shrink sleeve be?
The layflat should give a tube circumference slightly larger than the widest point so it slides on easily, then shrinks down. The calculator adds a slip clearance of about 3 mm to the half-circumference for the layflat, and your vertical shrink allowance (2% by default) plus press snap-back to the height so the sleeve still covers your target after it shrinks.
Which shrink film shrinks the most?
High-shrink PETG grades reach around 78%, which is why PETG dominates full-body sleeves over complex shapes; standard grades are nearer 55%. PVC and OPS sit around 55 to 65%. Standard PETG hurts PET bottle recycling, so ask about crystallizable PET or a floatable polyolefin sleeve if recyclability matters. Always confirm the exact shrink curve with your converter for your container geometry.
Could a label do the job?
PackOS doesn’t print or apply shrink sleeves. Quick Quote prices custom pressure-sensitive roll labels today — if a wrap label can replace the sleeve (compare them in shrink sleeve vs pressure-sensitive labels), upload the artwork for an instant label quote.