Custom Mil Mylar Bags
Custom mylar bags in 3.5, 5 and 7 mil, from 100 units, with a plain explanation of what the number means — because most buyers order the thickest bag they can find when what they needed was a better barrier, and pay twice for it.
What the mil number does and does not tell you
- Gauges
- 3.5, 4, 4.5, 5 and 7 mil; other gauges to order
- Barrier
- Aluminum foil laminate or metallized PET, specified separately from gauge
- Structures
- PET / foil / PE, PET / met-PET / PE, kraft-faced variants
Get a price for Mil Mylar Bags
Send the size and quantity — we reply the same working day with a price, a dieline and a date. Artwork optional at this stage.
- Free dielineThe flat drawing comes with the quote, before you commit.
- Proof before pressNothing is printed until you have seen it laid on the dieline.
- Die kept for reordersTooling is paid once. Every reorder skips straight to press.
- Quoted in four marketsUS, UK, Canada and Australia, in the delivery currency.
Thickness is not barrier
The oxygen and moisture barrier in a mylar bag is the aluminum layer in the middle of the laminate. A foil layer stops oxygen almost completely; a metallized coating, sprayed onto plastic, stops it far less well. Neither has much to do with the mil number, which is mostly the polyester and polyethylene around them. A 7 mil metallized bag has a worse barrier than a 4 mil foil bag, and costs more.
So the first question is foil or metallized, and the second is gauge. Most buyers ask them in the wrong order.
What each gauge is for
Gauge buys puncture resistance and stiffness. A 7 mil bag survives a sharp corner of dried pasta; a 3.5 mil bag does not. It also stands up straighter, seals with a wider window of temperatures, and costs roughly double the 3.5 in film.
| 3.5 mil | Retail snacks, treats, samples — flexible, cheap, folds flat, short shelf life |
|---|---|
| 4–4.5 mil | General retail with a zipper; the pouch most brands use most |
| 5 mil | Long-term storage, freeze-dried, dry goods; the puncture and seal margin |
| 7 mil | Sharp or dense contents, bulk weights, rough handling; stiff and heavy |
Where a thicker bag makes things worse
- Small retail bags — a 7 mil pouch for an ounce of product is stiff, will not lie flat, and reads as clumsy in the hand. The small format we build at 3.5–4 mil is on our mini mylar bags page for single servings.
- Zippered bags opened daily — thick film fights the zipper and the bag springs open.
- Anything heat-sealed on a light domestic sealer — 7 mil needs a longer dwell than many sealers give, and a weak seal is worse than a thin bag.
- Freight — film is sold by weight, and the thicker bag ships heavier in both directions.
Choosing in the right order
Decide the barrier from the shelf life: metallized for weeks to a few months, foil for a year and beyond. Then decide the gauge from the contents: 3.5–4.5 for soft retail products, 5 for storage, 7 for anything that could punch through. Then decide the format — flat, stand-up, gusseted — and the print. We walk through the storage version of that in more detail on our mylar bags for freeze-dried storage page, where the foil layer is not negotiable.
If a supplier will not tell you whether a bag is foil or metallized, assume metallized. The mil number is often the only figure quoted because it is the flattering one.
Mil Mylar Bags — specification
The rows that are specific to this build first, then what applies to every job we run. Anything not listed is a question, not a limit — send the brief.
This build
- Gauges
- 3.5, 4, 4.5, 5 and 7 mil; other gauges to order
- Barrier
- Aluminum foil laminate or metallized PET, specified separately from gauge
- Structures
- PET / foil / PE, PET / met-PET / PE, kraft-faced variants
- Styles
- Flat, stand-up, side and bottom gusset, zipper, tear notch
- Up to 10 colors on every gauge
- Minimum
- 100 bags
On every job
- Print process
- Flexo in up to ten colors on the outer film, or digital for short runs and changing artwork.
- Color
- A white underprint carries normal color on metallised or clear film. Without it, every color takes on what is beneath it.
- Tolerance
- Bag width plus or minus 2 mm, length plus or minus 3 mm. Film stretches, so a barcode is verified on a filled bag.
- Tooling
- Print plates or cylinders per design, kept. There is no cutting die — the bag is formed and sealed rather than cut.
- Food contact
- A food-grade sealing layer against the product, with the inks trapped between layers rather than on the food face.
- Sustainability
- Mono-material PE or PP where the shelf life allows, which recycles as a soft plastic. A foil laminate does not.
- Artwork
- Vector PDF or AI, 3 mm bleed, 4 mm safe area, fonts outlined. We check every file and send a proof before press.
- Dieline
- Supplied free with the quote, before you commit. Yours whether or not you order.
- Sample
- A plain unprinted sample at the finished size on request, for fit and construction.
- Reorders
- Skip the tooling and go straight to press at a lower unit price.
- Lead time
- Quoted with the price against your fill date rather than promised before we have seen the spec.
- Markets
- United States, United Kingdom, Canada, Australia — priced in the delivery currency, freight included.
Boards and films we build mil mylar bags on
A flexible pack is a stack of films laminated together, and the middle layer is the barrier. The structure is chosen from the shelf life you need and what you want to be able to say about recycling.
PET / PE
A printable outer and a sealing inner. Moisture barrier, modest oxygen barrier. The everyday laminate for dry goods sold quickly.
2-ply, 70–110 micronPET / AL / PE
Aluminum foil in the middle: the strongest barrier against light, oxygen and moisture. Coffee, supplements, anything with a long shelf life.
3-ply, 90–130 micronMetallised PET
A vapour-deposited metal layer. Bright, lighter and cheaper than foil, with a weaker barrier. Most silver and gold bags are this.
2–3 plyMono-material PE
Every layer polyethylene, so the bag recycles as a soft plastic. Less barrier and a slightly softer hand; the sustainable choice where shelf life allows.
100–130 micronMono-material PP
Stiffer and clearer than PE, with better heat resistance. Suits a stand-up pouch that has to hold its shape on a shelf.
90–120 micronKraft-paper laminate
A paper outer over a film barrier. The natural look with a real barrier behind it; the paper takes only a matte, flat print.
Paper 60–80gsm + filmCompostable film
PLA and cellulose structures certified for industrial compost. Lower barrier, higher cost, and no home-compost claim unless the certificate says so.
60–90 micronLDPE mailer film
Co-extruded opaque film for shipping bags: tear- and puncture-resistant, weatherproof, and recyclable where soft plastics are collected.
60–80 micronNot sure which? Say what goes in it and where it is sold — the material follows from that. Our notes on recycled, recyclable and compostable cover which claims each stock can honestly carry.
- 01
Send what you have
A dimension, a photograph beside a ruler, or the product itself. No technical drawing needed — that part is ours.
- 02
We quote and draw
A price, a dieline and a date come back together. If a different build would suit the product better, that is in the reply too.
- 03
Approve the dieline
The flat drawing is yours to check: which panel is the front, where the folds fall, how deep the cavity really is.
- 04
Artwork on the dieline
You place your design on the flat we sent, or we place it for you, and you see a proof before anything goes to press.
- 05
A sample if you want one
A plain unprinted sample at the finished size shows fit and construction — the things a drawing cannot.
- 06
Cut, printed, shipped
The die is cut once and kept, so every reorder skips the tooling and goes straight to press at a lower unit price.
Format
Vector PDF or AI where possible. Raster artwork at 300dpi at final size, in CMYK.
Bleed
3 mm past every trim line, so a fraction of drift on the cutter never leaves a white edge.
Safe area
Keep type and anything important 4 mm inside the cut and away from every fold.
Color
Convert to CMYK before sending. Uncoated stock prints lighter; a spot color is the only exact match.
Fonts
Outline them or supply the files. A missing font substitutes silently and the proof will not match.
Barcodes
On a light, matte, unvarnished patch with the quiet zone clear — a code on gloss fails the scanner.
Not set up that way? Send it anyway — fixing a file is a short conversation, and we check every one before press. Our guide to preparing print files covers each point.
Film is finished in the lacquer and the ink, not with a laminate.
Matte lacquer
A soft, non-reflective face. Hides handling marks and the most-used finish on a premium pouch.
Gloss lacquer
Wet-looking color. Reads cheaper on some categories and exactly right on confectionery.
Spot matte on gloss
A matte shape on a gloss field, or the reverse. The film equivalent of spot UV.
Metallised effects
Print over the metal layer so a color picks up the shimmer, or lay white under it for a normal color.
Registered emboss
A raised texture pressed into the film. Rare, expensive, and unmistakable in the hand.
Kraft-paper face
A paper outer laminated to the barrier. Matte and flat by nature; no varnish needed.
Not sure which suits the shelf it sells from? Say where the product is sold and we suggest one — our notes on specialty finishes show them on real boxes.
Sizing a pouch by what goes in it, not by a bag size: mil mylar bags
Film packs are specified by fill, not by dimensions. Two products of the same weight can need very different bags, because density decides volume — whole coffee beans take far more room than the same weight of powder.
- Fill weight and density
- Give us both, or send the product. We size from the volume it actually occupies, settled.
- Lay-flat width
- Half the circumference of the finished bag. It is the number a converter works to, and we calculate it from your product.
- Headspace
- Enough film above the fill to seal cleanly and for the bag to stand. Too little and the seal traps product; too much and the pack looks underfilled.
- Gusset
- Bottom gusset depth sets how the bag stands; side gussets add volume without width. Both are chosen from the shelf, not the fill.
- Seal width
- 5–8 mm. Wider on liquids and creams, which contaminate a seal, and on anything that will be posted.
- Sample fill
- A plain bag at the finished size, filled from your line, is the only reliable check before print.
Not sure your numbers are right? Send the product dimensions rather than the box dimensions and we work the box out — the full method is in our guide to measuring for a box.
Interactive · five steps · no sign-up
Spec your Mil Mylar Bags
Pick a shape, type a size, choose a film and a finish. The preview on the left redraws as you go, and the spec lands with us exactly as you set it.
Frequently asked questions
Got a question about mil mylar bags? The answers below cover what we get asked most. If yours is not here, send it with a brief, message us on WhatsApp, or call +1 503-461-4788 — we reply the same working day.
What does mil mean?
One thousandth of an inch of total laminate thickness. It measures the bag, not the barrier.
Is a thicker bag a better barrier?
No. The barrier is the aluminum layer — foil or metallized — and it is largely independent of gauge. A 4 mil foil bag beats a 7 mil metallized bag on oxygen.
Which gauge for long-term food storage?
5 mil with a true foil layer. 7 mil if the contents are sharp or dense enough to puncture.
Which gauge for a retail snack pouch?
3.5–4.5 mil. Thicker film is stiff in a small pouch and fights the zipper.
Do all your gauges come in foil?
Yes. Foil and metallized are both available in every gauge; you choose the barrier and the gauge separately.
Does 7 mil seal on a home impulse sealer?
Usually, with a longer dwell. Some light sealers do not get through it. Tell us your sealer and we will confirm.
Is 7 mil smell-proof?
Smell is stopped by the barrier layer, not the thickness. A foil bag of any gauge is effectively odor-tight when sealed; a thick metallized one is not.
How much more does 7 mil cost than 3.5?
Roughly double in film, before print. Freight is also higher because the bags weigh more.
Can I have different gauges in one order?
Yes, by size. A 3.5 mil sample bag and a 5 mil retail bag in the same print run is common.
What is the minimum order?
100 bags per size and gauge. Printed mylar runs on a roll, so the set-up is in the plates.
How long does production take?
It depends on the structure and the print. We give a date with the quote rather than a number before we have seen the spec.
Will you send samples in different gauges?
Yes, unprinted bags in two or three gauges so you can fill, seal and handle them before deciding.
Same range
