GSM vs. Point: Understanding Paper Thickness, Weight, and Caliper in Packaging

GSM vs. Point: Understanding International Paper Weights

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Choosing between GSM and Point can be confusing when sourcing packaging or print materials. Understanding the difference between GSM vs. Point is essential to selecting the right paper stock. This guide will break down everything you need to know about these units of measurement and how they impact print quality, durability, and packaging performance.

Measuring paper weight is determined by the material’s thickness or gauge using a caliper. Calipers are inexpensive and come come in dial, sliding, or digital options. See some caliper examples below or check out this article on the 8 best calipers for precise measurement in 2025.

GSM vs. Point Caliper

Now here's where it gets confusing...

While the rest of the world is happily using the metric system, the United States is holding on strong to the use of the British Imperial System for weights and measures

While we thankfully no longer measure things in units of barleycorn (yes, really, its equal to 1/3rd of an inch), the United States still uses measurements like inch, foot, yard, etc. 

Your caliper may read in point (1/1000th of an inch), GSM (grams per square meter), or both.

The Point System (pt)

The Point (pt) system is used primarily in the United States and measures the thickness of paper in thousandths of an inch.

  • Utilized in the United States
  • A point equals .001”, which means that 20-point board would be 0.02” thick
  • The higher the PT, the thicker the material
  • Measurements are only for thickness and do not take into consideration the stock weight of the material

Unlike GSM, the point system only accounts for thickness, not weight. That means two sheets with the same point rating can still feel different depending on the material.

Grams per Square Meter (GSM)

GSM stands for “grams per square meter” and measures the weight of paper. It’s the most common metric measurement used globally, especially outside the U.S., to quantify how heavy or dense a paper is.

  • Commonly utilized in China and globally
  • Uses centimeters and meters for its key measurement
  • The higher the GSM, the thicker the material
  • Measurements consider weight, length, and breadth of the material rather than just the thickness

GSM does not directly equate to thickness, but it gives a good approximation. The higher the GSM, the thicker, more durable sheet you get.

Material Matters!

Because GSM measurements are a ratio of thickness and weight, you cannot use point and GSM interchangeably. A 18-point coated 2 side (C2S) will weigh more than 18-point brown Kraft paper. These measurements describe single sheets of paperboard. Corrugated board is rated differently: on custom corrugated packaging, board grade and flute profile determine the strength, and caliper is only one input.

Conversion At-A-Glance: GSM vs. Point

To help our customers quickly compare paperboard conversions, PAX Solutions created the paperboard conversion chart below. This chart lists the conversion for coated 1-sided board in point, millimeters, and gsm. To view conversion charts for coated 2-sided and greyboard, please visit our Packaging Resources page.

paperboard conversion chart; gsm vs. point

Which Should You Use: GSM or Point?

Use GSM when:

  • You’re sourcing internationally
  • Weight is more important than thickness
  • You want a universal measurement across different material types

Use Point when:

  • You need to know how thick something is for packaging
  • You’re sourcing material from U.S. suppliers
  • You care about how the paper feels or stacks

FAQs

Q: Is GSM the same as thickness?
A: No. GSM is weight.

Q: How do I convert GSM to pt?
A: There is no fixed formula. Ask your packaging supplier or check out our Packaging Resource Charts.

Q: What’s better for packaging, GSM or Point?
A: Use both. GSM tells you durability; Point tells you structural thickness. Also, depending on where you are getting your packaging (Import or Domestic), you may find your supplier will communicate in one or the other.

Understanding the relationship between GSM, Point, and caliper helps you make informed packaging decisions. Whether you’re sourcing from China, Europe, or the U.S., use both metrics to choose the right material.

Need help deciding? Contact us to get expert guidance tailored to your next print or packaging project.