When sourcing custom packaging, understanding paper weight is crucial for selecting the right materials. But what exactly does GSM stand for, and how does it correlate to thickness? Here’s a simple breakdown of the paper weight system and its connection to density.
What is GSM?
GSM refers to grams per square meter, a measurement used to indicate paper density. It represents the weight in grams of one square meter of paper.
The higher the GSM number, the heavier and thicker the paper will be. For example, a 200 GSM paper will be thicker than a 100 GSM paper.
Factors Affecting GSM:
- Fiber source - Dense wood fibers produce higher GSM than plant fibers.
- Pulp concentration - More condensed pulp results in higher GSM.
- Processing - Calendering compresses paper fibers for increased density.
- Additives - Fillers like clay also add weight.
GSM Ranges for Packaging Papers:
- Textweight (45-90 GSM) - Typically used for book pages and commercial printing. Too lightweight for most packaging.
- Coverweight (91-150 GSM) - Ideal for postcards, brochures, and light folding cartons. Provides some structure while remaining flexible.
- Cardstock (151-300 GSM) - Used for business cards, greeting cards, hang tags, inner partitions and rigid paper boxes. Provides good stiffness and tear resistance.
- Paperboard (301-600 GSM) - Constructs cardboard boxes, displays, signage, rigid mailing envelopes, checkout counter mats, and more. Very rigid and durable.
- Corrugated Board (600+ GSM) - Extremely thick paperboard bonded with corrugated ribbing. Creates corrugated boxes and durable shipping containers.
Most everyday cardboard packaging and boxes fall into the 200-400 GSM paperboard range. Lighter cardstocks can be used as inserts and partitions. Heavy, dense stock can produce indestructible floor displays and signs.
Translating GSM to Paper Thickness:
While not perfectly precise, these average thicknesses provide a general estimate:
- 60-120 GSM = 0.06-0.15mm
- 130-180 GSM = 0.16-0.25mm
- 200+ GSM = 0.22mm+
Four Examples of Paper Weight vs Thickness
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So in summary, the higher the GSM number, the thicker and heavier the paper. When selecting custom packaging materials, use the GSM categories and thickness estimates as a helpful guide. Consider factors like desired strength, rigidity, and appearance. With a basic understanding of paper weight, you can confidently source the perfect paper stock for your brand’s boxes and packaging.
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