When you order poly bags, reclosable bags, or gusseted bags, you may notice slight variations in width, length, or thickness. These are called industry tolerances. We make sure every bag meets strength and durability standards, even with slight dimensional differences.
What Are Plastic Bag Tolerances?
Tolerances are the acceptable variations in a bag’s width, length, or gauge (thickness). These differences aren’t defects. They’re normal outcomes of the manufacturing process that still meet performance standards.
Why Tolerances Matter
Tolerances add flexibility to your packaging needs. A slight size variation won’t affect performance, especially when using quality bags.
In our experience, customers who understand tolerance standards rarely encounter sizing issues. Most account for slight variations when they choose bags with a bit of extra room, usually an inch or two, which deliver a reliable fit.
While it’s uncommon for any product to fall outside the specified tolerances, if you ever receive bags with dimensions or thicknesses beyond the accepted range, our team is always available to resolve the issue quickly.
Gauge Tolerances (Thickness of Plastic Bags)
Gauge refers to the thickness of the plastic. The industry-standard tolerance is ±10%, meaning a 4-mil bag may measure between 3.6 and 4.4 mil.
Packaging Friends consistently meets or exceeds these tolerances for all mil ranges.
Example Table
| Listed Thickness | Allowed Tolerance | Description |
|---|---|---|
| 1–3 mil | ±10% | Standard range for light and medium-duty use |
| 4–8 mil | ±10% | Heavy-duty or industrial-grade poly bags |
Width Tolerances
Acceptable width variation depends on the bag's overall size.
Example Table
| Size Range (Width) | Width Variance |
|---|---|
| Under 4 inches | +1/8" to -1/16" |
| 4 to 14.99 inches | +1/4" to -1/8" |
| 15 to 29.99 inches | +1/4" to -1/4" |
| 30 to 59.99 inches | +1/2" to -1/4" |
| 60 to 99.99 inches | +1" to -1/2" |
| 100 inches and above | ±2 |
These tolerances deliver consistent sizing across our entire product range.
Length Tolerances
Length is measured from the opening to the bottom seal (or just under the zipper for reclosable bags).
Example Table
| Size Range (Length) | Length Variance |
|---|---|
| Under 6 inches | +1/8" to -1/16" |
| 6 to 12 inches | +1/4" to -1/8" |
| 12.01 to 23.99 inches | +1/4" to -1/4" |
| 24 to 59.99 inches | +1/2" to -1/4" |
| 60 to 119.99 inches | +1" to -1/2" |
| 120 inches and above | ±2% |
We follow strict QC checks to make sure these ranges are upheld for every order.
How to Measure Poly Bags Correctly
You should take accurate measurements for your poly bags to fit correctly. Here’s how to measure:
●Width: measured across the open end.
●Length: measured from the opening to the bottom seal.
●For reclosable bags, measure from just below the zipper to the bottom.
Our tip is to choose a slightly larger size to account for normal tolerance variations. For detailed measurement formulas and examples, see Measure the Right Poly Bag Size for Your Packaging Needs.
What If You Need Tighter Tolerances?
Most customers don’t need special tolerances for their poly bags. If, however, you have sensitive components or automated systems, we can produce custom bags with tighter dimensional controls to fit your needs.
Contact our friendly team here at Packaging Friends to let us know the exact specs or large-volume custom runs. Orders over $1,000 qualify for free shipping with bulk discounts.
Packaging Friends for Your Plastic Bags
Width, length, and gauge tolerances are a normal part of poly bag production. Once you know the type and size of poly bags you need, you can order them to fit your products, with tolerances in mind.
To learn how bag appearance and packaging presentation differ between domestic and imported products, see Poly Bag Appearance and Packaging: What You Need to Know. And if you want more information about how thickness affects strength, check our guide Understanding “Mil” Thickness in Plastic Products.
Frequently Asked Questions
Are tolerance variations normal in poly bag manufacturing?
Yes, all plastic bag thickness and dimensions have small, industry-approved variations.
Why do larger bags have different tolerances than smaller ones?
Larger bags have more variance during production due to material stretch and cooling.
How can I make sure my bags fit correctly?
Measure your items carefully and choose a bag slightly larger than the product dimensions.
Do thicker bags have less size variation?
Not necessarily, but thicker poly bags tend to hold their shape more consistently.
Can I order bags with stricter polybag gauge control?
Yes, Packaging Friends can custom-produce bags with tighter tolerances upon request.