A customer buys two candles and a coffee mug, you slide them into a bag, and by the time she's at her car the bottom's given way. That's not bad luck — it's the wrong bag for the job, and it happens more often than it should, because most small business owners buy bags by price and picture, not by the number that actually tells you how strong a bag is.
That number is 'Mil,' and it shows up on almost every listing for merchandise bags, freezer bags, and storage bags without much explanation attached. Here's what it actually means, and how to pick the right one for what you're selling or storing — instead of guessing and finding out the hard way.
What 'Mil' Actually Means
A mil is one-thousandth of an inch. It's not a quality score and it's not the same as 'heavy duty' marketing language — it's a physical measurement of how thick the plastic film actually is. A 1.5 Mil bag is thinner than a 2 Mil bag, full stop, regardless of what either one is called on the package.
That's the whole concept. The harder part is knowing which thickness fits which job.
Match the Bag to What's Going Inside It
Light, soft, or small items — folded clothing, candles, jewelry, a greeting card — do fine in a 1.5 Mil bag, like a standard 9x12 handled merchandise bag. There's nothing in there sharp or heavy enough to test the plastic.
Bulkier or heavier purchases change that math fast. A stack of books, a boxed candle set, ceramics, anything with a real corner or edge — that's when a 2 Mil bag, usually the larger 12x15 size, earns its keep. The extra thickness isn't overkill there; it's the difference between a bag that survives the walk to the car and one that doesn't.
Freezer and Food Bags Play by Their Own Rules
Food bags need thickness and a seal that actually holds, because the failure mode is worse than a torn merchandise bag — it's a leak in someone's freezer. Quart-size freezer bags typically run around 2 Mil, gallon bags closer to 2.4 Mil, and anything holding a full 2 gallons of fruit or berries should be over 3 Mil with a double zipper, since wet, heavy contents put real pressure on the seams.
If a freezer bag listing doesn't mention a specific thickness at all, that's worth noticing. It usually means there isn't much to brag about.
Thicker Isn't Automatically Smarter
It's tempting to just order the thickest bag available for everything, but that costs more per unit for no real benefit on light items, and it adds up fast at volume. A 2 Mil bag for a single greeting card is money spent on strength nobody needed.
A Quick Check Before You Order
Fold a sample bag over your fingers. A 1.5 Mil bag feels noticeably more flexible than a 2 Mil one — you can feel the difference before you ever load anything into it. And when comparing suppliers, look for an actual Mil number in the listing, not just words like 'extra thick' or 'premium' standing in for one. Those words don't tell you anything a number would.
Getting the thickness right isn't complicated once you know what the number means. It just takes matching the bag to the actual weight and shape of what's going inside it, every time, instead of grabbing whatever's cheapest or whatever's already on the shelf.