What Thickness Mylar Bag Do You Need for Food Storage? (2026)

The short answer: 5 mil per side

If you take nothing else from this, take this: 5 mil per side is the standard for home food storage, and it is what we'd put on the shelf for rice, beans, wheat, oats, sugar, and flour meant to last decades. It is thick enough to resist the punctures that dry grains cause, sturdy enough to survive normal handling, and still thin enough to seal with a clothes iron. The question that kicks off most thickness threads is really a question about the floor, not the ceiling:

Is 3.5 millimeters thick enough for long term food storage? Or should I wait for the 5 mil to restock?

The community answer to that one is consistent: wait for the 5 mil. Thin "economy" bags in the 3.5 to 4 mil range are fine for short-term or a bag-in-a-bucket setup, but for a 25-year staple you want the extra margin. Here's the whole range at a glance.

The label trap: "per side" versus "total" mil

This is the part the vendor blogs skate past, and it's the single most useful thing to understand before you spend a dime. A Mylar bag has two walls. Some brands rate the mil of one wall ("per side"), and some rate both walls added together ("total"). So a bag advertised as "10 mil" is very often a 5-mil-per-side bag with the two sides doubled up in the marketing, while a bag advertised as "7 mil" may mean 7 mil on each side, which is genuinely thicker.

That is not a hypothetical. A well-regarded 5-mil bag from Wallaby is sold as "10 Mil Total," and a heavy-duty PackFreshUSA bag is sold as "7 Mil Thick (Per Side)." Same shelf, and the smaller-sounding number is the thicker bag. Once you know to ask "per side or total?" the numbers stop lying to you. And on the cheap end, the ratings get looser still:

Was looking on amazon for 1gal, at least 7mil thick mylar bags for storing food long term. Founds lots claiming to be 7mil or more, but pretty consistently the reviews stated that theyre nowhere near what the stated thickness is

That's the practical takeaway on no-name bags: treat a bargain "7 mil" listing with suspicion, buy from a brand that states its rating clearly, and judge a bag by its stiffness in hand more than the number on the box.

When 5 mil is plenty (which is most of the time)

For the everyday deep-pantry staples, 5 mil per side does everything you need. Dry beans, wheat berries, oats, sugar, and flour sit quietly in it for decades without working a hole through the wall. It heat-seals with an ordinary iron or a cheap impulse sealer, and dropped into a food-grade bucket for physical protection, it is the setup the whole long-term-storage world runs on. If your storage is indoors, reasonably climate-stable, and packed with ordinary staples, you are done at 5 mil.

If you're still working out the rest of the system, the thickness is only one piece. Our companion guide on how many oxygen absorbers you need for a bucket or bag covers the absorber side, and the shelf-life chart for dry staples shows what actually lasts once it's sealed.

When to go 7 mil

There are real reasons to spend up, and they come down to what's going in the bag and what's living near it. Sharp or heavy contents are the first: a thicker wall resists the grains that poke through a thinner one. As one owner lays out, the food itself decides how much puncture resistance you need:

Depends on the item you're storing. Smooth beans like black beans or kidney, navy or red beans or products like barley ordry milk or flour don't generally puncture. Garbanzo beans, many macaroni products, will puncture. Rice may puncture, depending on how sharp the grain is.

The other reasons are rodents, decades-long storage in a rougher environment like a garage or barn, and any situation where the bags get stacked, shifted, and handled a lot. In those cases the extra dollars for 7 mil per side buy real insurance. For a climate-controlled closet full of smooth beans and rice, they mostly buy peace of mind you didn't need.

Thicker bags are harder to seal

Thickness has a cost beyond price, and it catches people off guard: the thicker the bag, the more heat and dwell time it takes to fuse the seal. A household iron handles 5 mil comfortably. Push into true 7-mil-per-side territory and a weak sealer can leave you with a seam that looks closed but isn't, which is the worst of both worlds. Owners run into exactly this math:

most impulse sealers for mylar say they only do 10mil, but i have 7.5 mil bags, and if you include both layers its 15mil which probably wont work? I assume it should work if it gets hot enough, a thicker bag should at most need a longer heat cycle

The read is simple. At 5 mil, an iron or a basic impulse sealer is fine. If you're buying genuinely thick bags, buy a sealer that can keep up, and always run a finger-tug test on a cooled seam before you trust a bag with a year of food.

What thickness can't fix

Two honest limits, because no mil rating buys its way out of either. First, Mylar is not rodent-proof at any thickness a home storage bag comes in. A determined mouse chews through 7 mil as happily as 5, which is why the bag belongs inside a hard container, not on an open shelf:

I can attest, from personal experience, that mylar is not rodent proof. When I want to store foodstuffs in original packaging and/or mylar, it eventually winds up either in a bucket ($4-$5 with lid) or some other mouse proof container of similar thickness plastic.

Second, thickness has nothing to do with a vacuum. Mylar bags are heat-sealed, not vacuum-sealed, and an oxygen absorber does the air-removal chemically rather than sucking the bag tight. People new to it try to run Mylar through a vacuum sealer and get nowhere:

Do you have any tricks to getting your vacuum sealer to vacuum the 7 mil Mylar bags? I have a cheapo one and a large Weston and neither one will vacuum out the air with the Mylar.

So a correctly sealed bag will not look shrink-wrapped, and that's fine. The bag's job is to be an airtight, light-blocking, puncture-resistant wall; the absorber handles the oxygen and the bucket handles the mice.

So what should you buy?

For the overwhelming majority of home storage, buy a quality 5-mil-per-side bag, seal it with an iron or a basic impulse sealer, and drop it in a food-grade bucket. That combination stores your staples for decades and costs the least to get right. Only reach for true 7-mil-per-side bags if you're storing sharp or heavy foods, fighting rodents, or stashing food somewhere rough for the very long haul, and pair those with a sealer strong enough to close them.

Whichever you choose, read the label for "per side" versus "total," trust the feel of a stiff bag over a big printed number, and remember the thickness is only the wall. For which specific kits hold up, see our roundup of the best Mylar bags and oxygen absorbers.