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Views: 222 Author: Amanda Publish Time: 2026-02-05 Origin: Site
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● What Are GSM and PT in Packaging?
● Why GSM vs PT Matters for Modern Packaging Engineers
● Understanding the Point (PT) System in Packaging
● Understanding GSM (Grams per Square Meter)
● Common GSM Ranges and Their Packaging Uses
● Conversion Basics: From PT to GSM (and Vice Versa)
● Practical PT–GSM Reference Table for Folding Cartons
● How GSM and PT Affect Performance on Packaging Machinery
● Comparing GSM vs PT: Which Should You Prioritize?
● Step-by-Step: How to Choose the Right GSM and PT for Your Packaging
● Corrugated Board, GSM, and PT: Beyond Paperboard
● How GSM and PT Influence Printing Quality and Finishes
● Real-World Example: Choosing GSM and PT for a Cosmetics Folding Carton
● Design Implications: GSM, PT, and the Customer Unboxing Experience
● When to Talk to a Packaging Expert
● Take the Next Step with HLun Pack
>> 1. Is higher GSM always better for packaging?
>> 2. Can I convert PT to GSM using a single formula?
>> 3. What GSM is commonly used for folding cartons?
>> 4. Why does my board feel thick but still seem light?
>> 5. How do GSM and PT affect printing quality?
For HLun Pack and your customers, understanding GSM vs PT is critical to designing packaging that looks premium, protects products in transit, and runs smoothly on packaging machinery. Choosing the right combination of weight and thickness helps you balance product safety, cost, sustainability, and brand experience.
GSM (grams per square meter) and PT (points) are two complementary systems used to describe paper and paperboard used in packaging. Both are essential references when you need to get the right stiffness, print quality, and machinability for folding cartons, sleeves, inserts, and shipping boxes.
- GSM measures the weight of paper per square meter, combining weight, length, and width into a single value.
- PT measures the thickness of paperboard, where 1 point equals 1/1000 of an inch measured with a caliper.
- Both systems help you estimate rigidity, printability, and protection level for boxes, sleeves, and inserts.
In global packaging projects, you will often see GSM used in metric markets and PT used in North American contexts, which is why a clear understanding of both is essential for international brands.
Choosing the wrong GSM or PT can lead to boxes that crush in transit, print poorly, or jam on automated lines. The decision affects not only how the packaging looks, but also how it performs all the way from your factory to the end customer.
- Too low GSM or PT increases the risk of tearing, denting, and poor stacking strength.
- Too high GSM or PT can cause over-packaging, higher material cost, and potential issues on high-speed packaging machinery.
- The right balance influences shipping cost, product safety, sustainability goals, and customer unboxing experience.
For a professional packaging material manufacturer like HLun Pack, positioning your brand as a trusted advisor in GSM vs PT selection helps customers reduce total cost of ownership, not just material cost per box.
The point system expresses the physical thickness of paperboard in thousandths of an inch. It is especially important when you design folding cartons that must work on automated equipment and withstand mechanical stress.
- 1 point (1 pt) = 0.001 inch, measured with a caliper.
- Common folding carton ranges: roughly 8 pt to 24 pt for retail cartons and sleeves.
- Higher PT generally equals stiffer and thicker board, but not always heavier.
For example, a 17 pt uncoated paperboard can weigh around 350 gsm, while an 18 pt brown kraft can be thicker but still weigh less, showing that thickness and weight do not always move in the same direction. This is why PT alone cannot tell you everything about how a board will behave.
GSM measures how much a 1 m² sheet of paper or board weighs, making it a more holistic indicator of density, strength, and print quality potential. It is a widely accepted standard in the global packaging supply chain.
- Higher GSM typically means denser, more robust material.
- GSM takes into account weight, length, and breadth, not just thickness.
- In practice, higher GSM often correlates with better image reproduction and more premium handfeel.
However, a material may feel thick yet remain relatively light, especially in corrugated structures where fluting creates volume without adding much weight. This is why both GSM and PT, along with material type, need to be evaluated together.
These typical GSM ranges give a quick reference when you match board weight to application. They are not strict rules, but they provide a useful starting point for your specification work.
GSM Range | Typical Application |
35–55 gsm | Newspaper stock, very light and flexible. |
90–100 gsm | Standard office printer or copier paper. |
110–120 gsm | Premium bond paper for higher quality documents. |
120–140 gsm | Flyers and posters requiring moderate durability. |
210–300 gsm | Glossy brochures and high-end marketing collateral. |
350–400 gsm | Retail packaging cartons and business cards. |
For most primary packaging cartons, brands typically start evaluating between 300–400 gsm depending on product fragility, shipping conditions, and brand positioning.
There is no single universal formula to convert GSM to PT because the relationship depends on fiber type, coating, and manufacturing process. Nevertheless, understanding the logic behind both systems helps you use conversion charts correctly.
- GSM measures weight per area, while PT measures thickness, so different constructions can deliver the same GSM at different PT values.
- Coated boards, such as C2S SBS, will often have a higher GSM than uncoated boards at a similar PT, because coatings add mass.
- Density, moisture content, and fiber composition all influence the final pairing of PT and GSM.
The key takeaway is that conversion tables are practical tools and approximations, not exact scientific equations. Use them for comparison and specification, then confirm with real samples and test data.
The table below illustrates typical pairings of thickness (PT) and GSM for common packaging materials. Values are approximate, and actual numbers may vary by manufacturer and grade.
Thickness / Material | Approx. GSM |
13 pt pulp | 200 gsm |
14 pt uncoated | 270 gsm |
16 pt C2S / SBS | 350 gsm |
18 pt C2S | 400 gsm |
24 pt uncoated | 405 gsm |
24 pt C2S / SBS | 460 gsm |
40 pt cotton | 600 gsm |
This clearly shows that more thickness does not always mean more weight, reinforcing why both GSM and PT must be evaluated together when designing optimized packaging.
From a packaging machinery perspective, the right GSM and PT selection is essential for process stability and high throughput. Poorly chosen material can limit machine speed, increase waste, and drive up total cost.
- Feeding and folding: Board that is too thin can double-feed or crease poorly, while overly thick board may misfold or bounce in the magazine.
- Die-cutting and creasing: Consistent PT improves crease depth control, which is critical for automatic cartoning lines.
- Gluing and erecting: Stiffer, higher PT board may create stronger erected cartons but needs accurate glue application and sufficient compression time.
As HLun Pack offers both materials and machinery, you can guide customers to choose a GSM and PT combination that balances machinability, structural performance, and cost.
Both units play different but complementary roles, so the choice depends on your project's priorities. In most cases, the best approach is to consider them together rather than choosing one over the other.
Aspect | GSM Focus | PT Focus |
What it measures | Weight per unit area (density). | Thickness of the board in thousandths of an inch. |
Primary use | Costing, logistics, and print quality expectations. | Rigidity, stacking performance, and structural design. |
Best for | International vendor communication and freight estimations. | Die-line design and caliper-sensitive machinery settings. |
Limitations | Does not directly convey stiffness or caliper. | Does not account for board density or weight. |
Decision tip | Use when comparing materials from different suppliers globally. | Use when fine-tuning packing line performance and carton fit. |
In practice, experienced converters always review both GSM and PT, plus board type and construction, before approving a final specification.
Use this simple framework when advising clients on their packaging material selection. It helps turn technical numbers into practical decisions.
- Define the product profile. Consider weight, fragility, shape, and surface sensitivity, such as glass bottles versus plastic jars.
- Clarify logistics conditions. Identify whether cartons are shipped individually, in master cartons, or on pallets, and how long and harsh the transport will be.
- Set brand positioning goals. Decide whether the packaging should feel ultra-light, standard, or premium and substantial in customers' hands.
- Select an initial GSM and PT range. Use typical ranges like 300–400 gsm and 16–24 pt for folding cartons, then adjust based on early tests and supplier input.
- Test on packaging machinery. Run trials for feeding, creasing, gluing, and erecting speed to confirm machinability at scale.
- Optimize for cost and sustainability. Fine-tune to the lowest GSM and PT that still meet performance, visual, and brand standards.
This structured approach makes GSM and PT practical levers for performance, cost, and user experience, rather than abstract technical data.
In addition to paperboard, many packaging projects rely on corrugated board, such as single face, single wall, double wall, and triple wall constructions. These structures behave differently from solid board.
- Each corrugated type has its own GSM profile because it combines liners and fluting of different weights.
- Corrugated often feels thicker due to fluting, yet its overall weight can be relatively low compared with solid board.
- For shipping cartons, engineers prioritize edge crush test (ECT) and burst strength alongside GSM when they validate performance.
Using GSM intelligently in corrugated selection helps avoid unnecessary over-specification while still safeguarding products during long-distance shipping.
Print quality and finishing options are directly tied to board density, surface smoothness, and coating, which connect back to GSM and PT. The right choice can significantly enhance how your brand appears on shelf and online.
- Higher GSM and coated boards, such as C2S SBS, typically support sharper images, richer color, and finer detail.
- Uncoated or kraft boards deliver a more natural, sustainable look, but with slightly less vibrant print.
- Finishes like matte, gloss, soft-touch, foil stamping, and specialty varnishes often require a minimum caliper and GSM to perform consistently.
When brands plan heavy ink coverage or high-impact graphics, recommending a higher GSM coated board is often a reliable way to protect print integrity and perceived quality.
Imagine a premium skincare brand launching a fragile glass serum bottle and seeking a luxurious unboxing experience. The packaging must protect the product, communicate quality, and run smoothly on automated lines.
- Product: a small but heavy glass bottle with dropper.
- Requirements: high-end printing, embossed logo, and safe transport in e-commerce shipping.
- Recommended starting point: 350–400 gsm coated board, equivalent to around 16–18 pt C2S SBS, plus an internal insert or partition.
After machine trials and drop tests, the team might confirm that 18 pt C2S at 400 gsm balances rigidity, print quality, and cost, while ensuring the box runs efficiently on automatic cartoning lines. This then becomes the standard for that product family.
Beyond protection, GSM and PT shape the sensory impression customers have when they touch and open the packaging. These units become part of your brand language, even if customers never see the numbers.
- Higher caliper boards feel more substantial and luxurious, ideal for premium or giftable products.
- Lighter boards create an airy, minimalist feel, which can support sustainability narratives when communicated clearly.
- Correct caliper ensures boxes close snugly, maintain shape on shelf, and open smoothly without tearing.
By intentionally specifying GSM and PT, brands can align tactile experience, visual impact, and sustainability messaging in a coherent way that strengthens customer loyalty.
Even with a solid understanding of GSM and PT, complex projects benefit from expert support, especially when multiple materials and markets are involved.
- Multi-material packaging, such as combining folding cartons, inserts, and corrugated shipping boxes, requires system-level optimization.
- Brands operating across regions must reconcile metric and imperial frameworks with local manufacturing capabilities and supply constraints.
- Performance-critical applications like electronics, cosmetics, and food often require lab testing and certifications aligned with specific standards.
Working with an integrated partner like HLun Pack, who offers both material know-how and packaging machinery expertise, helps ensure that your final packaging performs reliably from factory to customer doorstep.
If you are planning a new packaging project and are unsure which GSM and PT combination will deliver the best balance of protection, cost, and brand impact, now is the ideal time to involve a specialist. Share your product details, shipping conditions, and visual goals with the HLun Pack team, and request tailored material recommendations, physical samples, and machine trials. Contact HLun Pack today to turn GSM and PT from technical jargon into a powerful, data-driven advantage in your packaging strategy.
Contact us to get more information!
No. While higher GSM often means stronger, more premium-feeling material, it can also increase cost and may not be necessary for lighter or well-protected products. The best GSM is the one that meets performance requirements with minimal waste.
No. Because GSM measures weight per area and PT measures thickness, different materials with varying density and coatings can have the same PT but different GSM, or vice versa. In practice, you rely on conversion tables and supplier data rather than a universal formula.
Many folding cartons are produced in the range of about 300–400 gsm, which often corresponds to roughly 16–24 pt depending on the exact board type. The final choice depends on product weight, desired rigidity, and printing needs.
Some constructions, especially corrugated boards with fluting, create thickness and volume without adding equivalent weight. As a result, the material can feel bulky and protective while still having a moderate GSM compared with solid board.
Higher GSM and coated boards usually provide smoother surfaces and better ink holdout, resulting in sharper images and more vibrant colors. Lower GSM or uncoated materials can still work well, but they may show more texture and absorb more ink, which slightly softens the printed image.
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[2]https://gwpg.com/wp/what-you-should-know-about-gsm-vs-pt-in-packaging/
[3] https://boxagency.co/blog/gsm-vs-pt-unit-system/
[4] https://urgentboxes.com/blog/difference-between-gsm-and-pt-unit-systems
[5]https://pakfactory.com/blog/gsm-vs-pt-unit-system/
