Laminating pouches are sold by thickness in mil — thousandths of an inch — and the figure refers to each side, not the total. A 5 mil pouch carries 5 mil of film on the front and 5 mil on the back, for 10 mil of material around the document.
That single detail causes most of the confusion, and thickness affects more than stiffness.
What each thickness is for
3 mil
Protects while staying flexible. A 3 mil laminated sheet still bends, so it files in a folder or binder without cracking at the fold. It is the economical choice for volume work.
Best for menus, instruction sheets, notices, reference material and anything filed rather than handled constantly. Not suitable for items that need to stand up on their own or survive daily handling.
5 mil
The most widely used thickness and the sensible default. Rigid enough to hold its shape and feel finished, thin enough that virtually every laminator accepts it.
Best for ID badges, luggage tags, shelf labels, membership cards, small signage and anything handled every day. If you buy one thickness for general office use, buy this one.
7 mil
Noticeably rigid — closer to thin card than to paper. It resists bending and stands up to repeated handling well.
Best for items living in workshops or storerooms, machine-side instruction cards, and signage under cover outdoors. Check your machine takes it before ordering; many entry-level laminators stop at 5 mil.
10 mil
Effectively a plastic card. Heavy, stiff and durable for years.
Best for heavy-duty tags, equipment labels and anything expected to survive rough treatment. It requires a laminator explicitly rated for it — feeding 10 mil through a machine that is not will produce a poor seal at best and a jam at worst.
Check your machine first
This is the mistake that wastes money, because pouches are usually bought in bulk.
Not every laminator accepts every thickness. A machine rated to 5 mil will not properly bond 7 mil film — thicker film needs more heat and more dwell time to activate the adhesive fully, and a fixed-temperature machine simply cannot supply it. The result is cloudy patches, edges that peel, or a jam.
Check the maximum pouch thickness in your laminator's specification before ordering. If you routinely use more than one thickness, choose a machine with selectable temperature settings rather than a single fixed setting — that flexibility is worth more than a slightly faster warm-up.
Thickness, heat and speed
The relationship is straightforward: thicker film needs more heat, and more heat needs more time in the rollers.
That is why better laminators offer a thickness selector and sometimes a speed control. Choosing the wrong setting is the single most common cause of poor results — too little heat for the film leaves the adhesive partly unactivated, which shows as cloudiness that never clears no matter how long you wait.
Running thin film too hot causes the opposite problem: ripples, wavy edges and occasionally a pouch that sticks to the rollers.
Pouch size and the margin that matters
Pouches are sold by document size — letter, legal, badge, business card, menu. Always leave at least 3mm of clear pouch around the document on every side so the adhesive can bond to itself and form a sealed border.
A document cut flush to the pouch edge has no seal at that edge, and moisture will eventually get in. If the item is smaller than the pouch or an unusual shape, centre it and accept the wider border, or trim afterwards leaving a margin intact.
Matt and gloss
Gloss is standard: it enhances contrast and colour, and it is what most people picture when they think of lamination. It also reflects, which can make a sign hard to read under overhead lighting.
Matt finishes reduce glare and are easier to read at an angle, which makes them worth considering for wall signage, instructions read at a distance, or anything photographed. Matt shows fingerprints less readily too.
A practical buying default
If you are stocking a general office, buy 5 mil letter in quantity and add 3 mil only if you regularly laminate things that need to bend. That combination covers the overwhelming majority of office laminating, and 5 mil is the size most commonly stocked, so replacements are easy to source.
Add 7 mil or 10 mil only for a specific, identified need — and confirm your machine's rating first.
Storage
Pouches keep almost indefinitely if stored flat, dry and away from heat. Stored upright or in a warm place they can bow or, at worst, begin to bond at the edges. Keep them in their box, lying flat, somewhere at room temperature.
Pouches and rolls are different systems
Everything above concerns pouch laminating, where the film comes pre-cut and sealed along one edge. Roll laminating feeds film from two continuous reels and trims afterwards.
Rolls are cheaper per square foot and suit high volume or oversized work, but they require a roll laminator, produce trim waste, and involve a genuine setup each time you change film. For the vast majority of office use — badges, signs, reference cards, menus — pouches are the right system, and the cost difference only becomes meaningful at volumes most offices never reach.
Common pouch sizes
Thickness is only half the specification; size is the other half. The sizes you will meet most often:
- Letter (9 x 11.5") — the general-purpose default for documents and signage.
- Legal (9 x 14.5") — longer documents and vertical signs.
- Badge and ID — several small formats, often sold with slot punches or clips.
- Business card — for reference cards and small tags.
- Menu (12 x 18") — oversized work, and the point at which roll laminating starts to make sense.
Buy the size closest above your document rather than trimming down from something much larger — trimming after laminating risks cutting into the sealed border, which is what lets moisture in later.
Shop by thickness: 3 mil pouches or 5 mil pouches. If your results are coming out cloudy or bubbled, our guide to laminating technique covers the fixes.
