When it comes to packaging and printing, one of the most common questions is: “How thick or heavy is this paper?” Two measurement systems are frequently used in the industry: GSM and PT (points). While both describe paper or cardboard thickness, they are different and understanding them is essential for designers, printers, and brands.
In this article, we’ll explain what GSM and PT are, how they relate to each other, and why knowing both is important when creating packaging, boxes, or printed materials.
What is GSM?
GSM stands for Grams per Square Meter. It measures the weight of paper per unit area. Simply put, it tells you how heavy one square meter of a sheet of paper is.
- A low GSM (like 80–120 gsm) indicates thin paper, typically used for flyers, notebooks, or magazines.
- A medium GSM (150–250 gsm) is common for postcards, brochures, and folding cartons.
- A high GSM (300+ gsm) is thicker cardboard or premium paper, suitable for packaging, business cards, or luxury print items.
GSM is widely used internationally, especially in Europe, Asia, and many packaging suppliers worldwide. It provides a precise weight-based measurement, which helps predict stiffness, print quality, and feel of the material.
Key points about GSM:
- Higher GSM usually means thicker, sturdier paper.
- Not all papers with the same GSM feel the same; finish and density also matter.
- GSM is more standard in the paper and packaging industry for international shipments or production.
What is PT?
PT, or points, is another way to measure paper thickness. In this system, 1 PT equals 1/1000 of an inch (0.001 inch). PT is often used in North America and is commonly applied to cardboard, cover stock, and rigid packaging.
For example:
- A 10 PT cardboard is thin, similar to a lightweight brochure.
- A 20 PT cardboard is medium thickness, suitable for folding cartons or greeting cards.
- A 40 PT or higher is considered thick rigid cardboard, ideal for premium gift boxes or hardcover books.
Unlike GSM, which measures weight, PT measures physical thickness. This is why two sheets with the same GSM can have slightly different PT measurements if their density or composition differs.
Key points about PT:
- PT is primarily used in the U.S. and Canada.
- It is easier to visualize in terms of stack height or box rigidity.
- It’s especially useful for rigid packaging, business cards, and specialty boxes.
GSM vs PT: How to Compare
While GSM and PT measure paper differently, it’s often useful to convert between them, especially when working with international suppliers. Here’s a rough guide:
- 120–160 GSM → ~8–12 PT
- 200–250 GSM → ~14–20 PT
- 300+ GSM → ~24–40 PT
Remember, the conversion depends on paper density and finish. A coated paper may be slightly thicker than an uncoated paper at the same GSM. That’s why professional packaging manufacturers usually check both GSM and PT before production.
Why Knowing Both Matters
For brands, designers, and packaging specialists, understanding GSM and PT is more than just numbers. It helps in:
- Choosing the right material: Ensuring your box, carton, or flyer has the correct rigidity and feel.
- Estimating shipping weight: GSM is directly linked to weight, which affects transport costs.
- Communicating with suppliers: International suppliers may prefer GSM, while North American partners may reference PT.
- Predicting product experience: Thicker paper or board improves perceived quality, especially for premium packaging.
For example, a luxury chocolate box or gift set in the UAE or Europe would often use high GSM cardboard (300+) or 30–40 PT board, which ensures a sturdy feel and high-end presentation.
