Find The Perfect Fit With a Guide To Mylar Bag Sizes

Ever bought the right product, but the wrong packaging?

You’re not alone. But with so many options out there, how do you know what actually fits your needs?

In this guide, we’ll cut through the confusion. From standard mylar bag thicknesses to choosing the right size for your product, you’ll learn how to avoid waste, save costs, and get packaging that works just as hard as your product does.

What Exactly Are Mylar Bags? 

Think of Mylar bags as the quiet heroes of long-term storage. They’re made from stretched polyethylene terephthalate (PET).

These bags are strong, flexible, and built with multiple laminated layers. That layered structure isn’t just for durability, it’s what makes them effective at blocking out moisture, light, heat, and even odors. In short, they act like a barrier between your product and anything that could ruin it.

That’s why Mylar is one of the most trusted packaging choices for food products, supplements, herbs, and even electronics. It’s lightweight, easy to seal, and built to keep contents fresh for longer.

Another plus? 

Mylar bags aren’t one-size-fits-all. They come in different thicknesses, meaning you can tailor your packaging to match how delicate your product is or how long you want it stored. And yes, most of them are recyclable and reusable, which makes them a responsible pick too.

What Are Standard Mylar Bag Thicknesses? 

Thickness matters more than most people think when it comes to packaging, and in the case of Mylar bags, it can directly impact how fresh, safe, and shelf-stable your product stays.

So, let’s break this down without getting overly technical.

“Mil” is the unit used to measure thickness in packaging. One mil equals one-thousandth of an inch. That means when you see a bag labeled “5 mil,” you’re looking at a thickness of 0.005 inches.

Mylar bags typically range between 2 mils and 7.5 mils. But not all of those are practical for storage, especially for food.

If you’re in the business of packaging products that need to stay fresh, resist moisture, and avoid light exposure, you’ll want to focus on bags at least 4.5 mils thick. Anything thinner often lacks the barrier strength to protect against UV, humidity, or even odors.

Here’s a simple breakdown of what the different thicknesses are best suited for:

3.5 – 4.5 mil Bags:

Good for basic, short-term storage. These thinner bags are flexible and affordable. ideal for items like spices, dry snacks, or pharmaceuticals that don’t need long-term protection. Just keep in mind: they won’t block out light completely.

5 – 6.5 mil Bags:

These are the go-to for brands that want to store products like pasta, rice, or dried herbs for longer periods. You get a better moisture and oxygen barrier, plus more durability during shipping.

6.5 – 7 mil Bags:

If long-term storage is your priority, this is the sweet spot. Bags in this range are thick enough to prevent UV exposure, resist punctures, and block air and moisture. Perfect for premium items like coffee beans, jerky, or emergency food supplies.

Mylar Bags Size Guide 

Small Sizes

• 9cm x 10cm (Mylar Pouch): Perfect for small product samples, spices, or single-use items.
• 10cm x 15cm (Standard & Black Zip Lock): Ideal for small snacks, coffee portions, or cosmetics. Comes in standard and black finishes for branding variety.
• 12cm x 20cm (Zip Lock): Suitable for slightly larger items like herbal mixes or small dry goods.
• 15cm x 15cm (Small Bag): A square option that works well for tea bags, small candies, or travel-size items.

Medium Sizes 

• 20cm x 25cm (Zip Lock): A solid mid-range size for dried fruits, grains, or supplements.
• 20cm x 30cm (Standard Mylar Bag): Offers a bit more room—good for meal prep ingredients, powders, or pet treats.
• 25cm x 35cm (Medium Bag): Available in standard and heavy-duty 7 mil thickness. A great pick for bulkier items or longer shelf life needs.

Large & Heavy-Duty Sizes 

• 25cm x 40cm (HD Zip Lock Bag): Heavy-duty zip lock option for products that need added protection from moisture, air, and handling damage.
• 35cm x 50cm (Heavy Duty Bag): Designed for larger quantities, perfect for food kits, protein powders, or storage that spans several months.
• 48cm x 74cm (Large Mylar Bag): Available in heavy-duty 7 mil thickness. This size works best for bulk storage, emergency supplies, or high-volume products.

How To Correctly Measure The Thickness? 

Let’s clear up a common confusion: measuring Mylar bag thickness isn’t about guessing or estimating based on feel. It’s about understanding what “mil” means and how that translates to real-world protection.

Thickness is measured in mils, not millimeters or milliliters. One mil equals one-thousandth of an inch (0.001″). 

So, a 5 mil Mylar bag is 0.005 inches thick. It may not sound like much, but in packaging terms, that’s a significant layer of protection.

Now here’s where it gets tricky:
The thickness you should choose isn’t just about the bag—it depends on what you’re storing, how long it needs to last, and the product’s size and weight.

For example:

• Lighter items or short-term use? You may be fine with 3.5 to 4 mil bags.
• Bulkier or long-term storage? Aim for 5 to 7 mils to ensure proper barrier protection against light, air, and moisture.

If you ever need to measure the thickness of a Mylar bag yourself, use a micrometer or caliper tool as these give precise readings. Just be sure to avoid measuring near seams or folds, as those can give you inflated results.

Does The Thickness of Mylar Bags Really Matter? 

Yes, it absolutely does.

A lot of businesses overlook thickness when choosing Mylar bags. They focus on size, seal type, or appearance. But if your goal is to protect your product and extend its shelf life, thickness is a decision-maker.

Let’s break down why it matters:

Better Barrier, Better Protection

Thicker Mylar bags (especially around 7 mil) offer stronger resistance to oxygen, moisture, and UV light. That barrier helps prevent spoilage, flavor loss, and degradation, especially for food, herbs, or supplements that need long-term storage.
Thinner bags, on the other hand, may feel cost-effective, but they can compromise quality by letting in the very elements you’re trying to keep out.

Stronger, Tougher, More Durable

Shipping or handling products with sharp edges? Thicker bags are less prone to punctures and tearing. That’s key when you’re storing bulk goods, vacuum-sealing, or just want to avoid waste from damaged packaging.

Built for Long-Term Storage

If you’re planning to store food for emergency use, bulk sales, or delayed consumption, you’ll need bags that hold up over time. Thicker Mylar bags keep their seal, structure, and effectiveness much longer, especially when paired with oxygen absorbers.

There’s a Cost But It Pays Off

It’s true: thicker bags cost more. But what’s more expensive, upgrading your packaging, or replacing spoiled product and disappointing your customers?

How To Choose The Right Thickness Of Mylar Bags? 

There’s no one-size-fits-all answer when it comes to Mylar bag thickness. The right choice depends on what you’re packaging, how long it needs to last, and how you want your brand to be perceived.

Let’s simplify how to approach this:

Start with Your Product

Ask yourself:

• Is the product fragile or sharp-edged?
• Does it need to stay fresh for months or years?
• Is it dry, oily, or moisture-sensitive?
  

For example, something like macaroni or jerky (which you might store long-term) needs a thicker bag, around 7 mil, to ensure protection from moisture and air. On the flip side, beans, spices, or flour might be perfectly fine in a 5 mil bag, especially if the storage period is shorter.

Match Thickness With Storage Time

• 3.5 – 4.5 mil: Best for short-term use or lightweight items. Budget-friendly and flexible, but not the strongest barrier.
• 5 – 6 mil: Ideal for medium- to long-term storage. Solid all-round protection without being too bulky.
• 7 – 7.5 mil: Heavy-duty. Designed for products that need to stay safe, dry, and intact for extended periods.

Don’t Forget Branding

Your packaging reflects your brand. A thinner bag may feel cheaper in hand while a thicker one instantly conveys quality, care, and long-term reliability. It’s not just about protection; it’s about presentation.

In a Nutshell 

Choosing the right Mylar bag thickness isn’t just a packaging decision, it’s a product protection strategy. Thinner bags work for short-term needs, while thicker bags offer stronger barriers and longer shelf life. The key is to align your bag’s thickness with your product’s size, sensitivity, and storage duration. Do that, and you’ll find the perfect fit every time.

Want something custom-made?

Packaging Unit delivers high-quality Custom Mylar bags tailored perfectly to your product dimensions—because your packaging should fit just as well as your product does.

FAQs 

Q: Why did Amazon stop selling Mylar bags?

Ans: Amazon restricted the sale of Mylar bags due to concerns about their potential misuse for illegal product storage. While the bags themselves are legal, Amazon opted to limit liability by removing certain listings, especially those without transparency around intended use.

Q: What are standard Mylar bag thicknesses in inches and cm?

Ans: Mylar bag thickness is typically measured in mils (1 mil = 0.001 inch). Here’s a quick conversion:

• 3.5 mil = 0.089 mm (0.0035 inch)
• 5 mil = 0.127 mm (0.005 inch)
• 7 mil = 0.178 mm (0.007 inch)

Q: What are standard Mylar bag thicknesses for food?

Ans: For food storage, the most common thicknesses are:

• 3.5–4.5 mil for short-term or lightweight items (like snacks, spices)
• 5–6 mil for medium to long-term storage (beans, rice, grains)
• 7 mil and above for long-term preservation (jerky, pasta, emergency supplies)