Laminating Pouch Size Guide

Pick the right pouch for the job

Laminating pouches come in sizes that match common paper and card formats, plus a thickness measured in microns. This guide pairs each document size with the pouch that fits it and recommends a micron thickness for the use. Pouches are slightly larger than the paper so a sealed border can form around the edge.

Understanding microns

Micron (mic) is the thickness of one side of the pouch. Common options are 75, 125, and 250 microns. Thicker pouches are stiffer and more durable but slower to laminate and harder to fold.

• 75 mic: light protection for documents you'll file, like menus or notices.
• 125 mic: the everyday all-rounder for signs, flashcards, and reference sheets.
• 250 mic: rigid, hard-wearing cards like place mats, ID tags, and outdoor signs.

Common pouch sizes

• A4: letters, worksheets, signs (most common).
• A3: posters and large charts.
• A5: half-page notices and menus.
• A6: postcards and recipe cards.
• Business card / ID: badges, tags, and wallet cards.

How to use this guide

1. Find your document size in the chart.
2. Choose the matching pouch size. It will be a few millimetres larger to seal the edge.
3. Pick a micron thickness for how hard-wearing the result needs to be.
4. Check the thickness is within your laminator's rated range before running it.

Notes and limitations

• Always centre the item in the pouch and leave the sealed border; trimming into the seal lets moisture in.
• Not all laminators handle 250 mic pouches. Check the machine's maximum micron rating.
• Use a carrier sleeve for older machines to avoid jams and uneven sealing.

Choosing a thickness for the job

Microns measure one side of the pouch, so a "250 micron" pouch is 125 microns per side. Thickness decides stiffness and how the item will be handled.

• 75–80 micron — thin and flexible. Suits documents that will be filed rather than handled, and it is the cheapest per pouch.
• 125 micron — the general-purpose choice. Holds its shape, still bends. Right for most classroom display work.
• 175–250 micron — rigid. The correct choice for flashcards, name badges, menus and anything handled daily by children.
• Above 250 micron — very stiff, and check your machine supports it before buying.

Two practical constraints: not every laminator handles the thickest pouches, and thicker pouches need a slower feed, so a cheap machine may jam or seal incompletely.

Why the pouch is bigger than the paper

A pouch sized for A4 is slightly larger than A4, and that margin is deliberate — it is the seal. Without a border of clear plastic all round, the laminate has nothing to bond to and will peel apart from the edge.

This has a consequence people meet the hard way: trimming right up to the paper after laminating destroys the seal. If you cut through the border, the layers separate and moisture gets in, which defeats the point.

If you need a smaller finished item, trim the paper before laminating and leave the pouch border intact afterwards. Where a neat edge matters, leave 3–5mm of clear plastic all round rather than cutting flush.

Getting a clean result

• Let the machine warm up fully. Feeding early is the commonest cause of cloudy, incompletely sealed laminate.
• Feed the sealed edge first, always. The folded edge leads; the open edge trails.
• Centre the item so the border is even. An off-centre item has a wide seal on one side and almost none on the other.
• Use a carrier if your machine came with one, particularly for thin pouches.
• Lay it flat to cool. Pouches curl if bent while warm, and the curl is permanent.
• Never re-feed a finished pouch to fix a patch — it distorts and can jam.

Cloudiness usually means too fast or too cool; bubbles and wrinkles usually mean the item shifted on the way in.

What not to laminate

Laminating is permanent, which makes it the wrong choice more often than people expect.

Anything you may need to write on with a normal pen. Dry-wipe markers work on laminate and are the point for reusable sheets, but permanent ink is a problem and pencil will not mark it at all.

Originals and documents of record. Certificates, passports and legal documents can be invalidated by lamination, and it cannot be reversed. Laminate a copy.

Photographs you care about. The heat can damage the emulsion on some prints.

Anything that changes. Timetables, class lists and price lists all get revised, and a laminated version out of date is worse than a paper one.