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Ever received a printing quote mentioning "80 lb cover" or "120 gsm" and felt completely lost?
Paper weight can be surprisingly confusing. Different countries use different measurement systems. North America primarily uses pounds (LB), while most other countries use grams per square meter (GSM).
In this guide, you'll learn everything about paper weight conversion from GSM to LB. We'll cover conversion formulas, practical applications, and how to choose the perfect paper weight for any project.
GSM stands for "Grams per Square Meter." This metric measurement represents exactly what it sounds like—how much one square meter of a particular paper weighs in grams. Unlike other measurement systems, GSM provides a straightforward way to understand paper weight.
The principle is simple: the higher the GSM number, the heavier and typically thicker the paper will be. This direct relationship makes GSM intuitive for professionals and consumers alike.
Measuring GSM involves a precise process:
For example:
This standardized approach ensures accuracy across different paper manufacturers worldwide. No complex calculations are needed to understand the basic weight.
GSM has become the international standard for paper weight for several compelling reasons:
| GSM Range | Feel | Common Applications |
|---|---|---|
| 35-55 | Very thin, semi-transparent | Newspaper, lightweight flyers |
| 70-90 | Thin but sturdy | Office copy paper, brochures |
| 100-120 | Medium thickness | Quality letterhead, premium flyers |
| 150-170 | Moderate thickness | Posters, quality brochures |
| 200-250 | Thick, solid feel | Business cards, postcards |
| 300+ | Very thick, rigid | Luxury packaging, premium business cards |
LB, short for pounds per ream, is a common way to describe paper weight in the United States and other parts of North America. It tells us how much 500 sheets of paper weigh before they are cut to standard sizes.
While most of the world has adopted the metric GSM system, North America continues to use the pound system. This creates a necessity for conversion when working with international printing projects.
American printers, publishers, and designers typically discuss paper in terms like "60 lb text" or "100 lb cover" rather than GSM measurements.
The pound system presents several notable challenges:
| Paper Type | Basic Size (inches) | What It Means |
|---|---|---|
| Bond | 17" × 22" | 500 sheets at this size = stated weight |
| Cover | 20" × 26" | 500 sheets at this size = stated weight |
| Text | 25" × 38" | 500 sheets at this size = stated weight |
| Bristol | 22.5" × 28.5" | 500 sheets at this size = stated weight |
| Index | 25.5" × 30.5" | 500 sheets at this size = stated weight |
The confusion becomes clear when comparing paper types. For example, "80 lb text" and "80 lb cover" sound similar but represent dramatically different weights and thicknesses. This happens because the basic sheet size for text paper (25" × 38") is significantly larger than cover paper (20" × 26").
This complexity makes the pound system less intuitive than GSM, particularly for those new to paper specifications or working across international boundaries.
To compare paper weights across systems, we need to convert between GSM (grams per square meter) and LB (pounds per ream). Since GSM is a metric unit and LB is imperial, the formulas differ based on paper type—Text or Cover.
Text paper, commonly used for books, brochures, and general printing, requires specific conversion formulas:
LB to GSM Conversion: GSM = LB × 1.48
GSM to LB Conversion: LB = GSM ÷ 1.48
For example, if you have 80 lb text paper and need to know its GSM equivalent:
GSM = 80 × 1.48 = 118.4 GSM
Conversely, if you have 100 GSM paper and need its text weight in pounds:
LB = 100 ÷ 1.48 = 67.6 lb
Cover paper, used for book covers, business cards, and sturdier applications, uses different conversion factors:
LB to GSM Conversion: GSM = LB × 2.708
GSM to LB Conversion: LB = GSM ÷ 2.708
For instance, converting 80 lb cover paper to GSM:
GSM = 80 × 2.708 = 216.6 GSM
And converting 250 GSM to cover weight pounds:
LB = 250 ÷ 2.708 = 92.3 lb
Understanding common paper weight conversions can save valuable time when working on print projects. Instead of calculating each conversion, reference these standard equivalents to quickly determine the appropriate paper weight across measurement systems.
Text paper is commonly used for books, brochures, flyers, and general printing purposes. Here's a comprehensive conversion table for text paper weights:
| GSM Value | Text LB Equivalent | Common Applications |
|---|---|---|
| 17 gsm | 11.5 lb | Tissue paper, lightweight wrapping |
| 22 gsm | 14.9 lb | Premium tissue paper |
| 30 gsm | 20.3 lb | Tracing paper |
| 45 gsm | 30.4 lb | Lightweight packaging material |
| 60 gsm | 40.5 lb | Lightweight documents |
| 75 gsm | 50.7 lb | Economy printing paper |
| 80 gsm | 54.1 lb | Standard office paper |
| 100 gsm | 67.6 lb | Premium letterhead |
| 105 gsm | 70.9 lb | Quality brochures |
| 110 gsm | 74.3 lb | Premium flyers |
| 115 gsm | 77.7 lb | Mid-weight brochures |
| 120 gsm | 81.1 lb | Professional documents |
| 130 gsm | 87.8 lb | High-quality flyers |
| 135 gsm | 91.2 lb | Premium documents |
| 140 gsm | 94.6 lb | Quality certificates |
| 150 gsm | 101.4 lb | Premium brochures |
| 157 gsm | 106.1 lb | High-end promotional materials |
| 160 gsm | 108.1 lb | High-quality posters |
| 167 gsm | 112.8 lb | Art prints |
| 170 gsm | 114.9 lb | Premium folders |
| 180 gsm | 121.6 lb | Premium booklets |
| 200 gsm | 135.1 lb | Luxury text applications |
| 210 gsm | 141.9 lb | Premium catalogs |
| 220 gsm | 148.6 lb | High-end menus |
| 230 gsm | 155.4 lb | Art booklets |
Cover paper is thicker and more durable, used for business cards, covers, postcards, and other applications requiring sturdier paper. Reference this conversion table for cover paper:
| GSM Value | Cover LB Equivalent | Common Applications |
|---|---|---|
| 200 gsm | 73.9 lb | Basic business cards, light covers |
| 210 gsm | 77.5 lb | Economy cover stock |
| 220 gsm | 81.2 lb | Lightweight postcards |
| 230 gsm | 84.9 lb | Standard postcards |
| 240 gsm | 88.6 lb | Quality brochure covers |
| 250 gsm | 92.3 lb | Quality business cards |
| 256 gsm | 94.5 lb | Premium presentation folders |
| 270 gsm | 99.7 lb | Premium postcards, invitations |
| 280 gsm | 103.4 lb | Book covers |
| 300 gsm | 110.8 lb | Professional business cards |
| 310 gsm | 114.5 lb | Luxury invitations |
| 320 gsm | 118.2 lb | Premium greeting cards |
| 350 gsm | 129.2 lb | Premium packaging, luxury cards |
| 360 gsm | 133.0 lb | High-end business cards |
| 400 gsm | 147.7 lb | Ultra-premium applications |
When selecting paper for your project, consider how these weights feel in hand. For example, standard copy paper is typically 75-80 gsm (50.7-54.1 lb text), while most quality business cards start at 300 gsm (110.8 lb cover).
For international projects, communicating in GSM usually reduces confusion. However, when working with North American printers, converting to LB measurements using these tables ensures everyone understands exactly what paper weight is required.
Selecting the appropriate paper weight dramatically impacts the success of any print project. The weight affects not only how your printed materials look and feel but also their durability, cost, and even shipping expenses. Understanding paper weight categories will help you make informed decisions for your specific needs.
Lightweight papers offer excellent versatility for everyday printing needs:
Lightweight paper works best when handling and durability aren't primary concerns. These papers typically have some degree of transparency, making them less suitable for double-sided printing where content bleed-through would be problematic.
Medium weight papers balance quality and practicality:
This range represents the most versatile paper category. The lower end (90-120 GSM) includes standard office paper, while the upper end approaches premium document territory with substantial feel without excessive stiffness.
Heavyweight papers communicate quality and importance:
These papers resist tearing and stand up to frequent handling. They're ideal when you want to convey importance or luxury, though they typically require scoring before folding to prevent cracking.
| GSM Range | Common Uses | Characteristics |
|---|---|---|
| 300-350 | Business cards, invitations | Professional, substantial feel |
| 350-400 | Premium packaging, luxury cards | Impressive rigidity, luxury impression |
| 400+ | High-end presentation folders | Maximum durability, ultra-premium feel |
Cardstock resists bending and maintains its shape even with frequent handling. While the most expensive option, it creates lasting impressions for high-value marketing materials and prestigious communications.
When selecting paper weight, consider not just appearance but practical factors like postal requirements, printing method compatibility, and whether recipients will need to write on the surface.
Tissue paper plays a crucial role in product packaging, gift presentation, and brand experience. Understanding the different weights available helps businesses select the perfect option for their specific needs. Weights for tissue paper are typically expressed in both LB and GSM measurements.
The lightest and most commonly used tissue paper weight offers several advantages:
A step up in weight provides enhanced quality:
Often referred to as white kraft paper, this weight brings substantial benefits:
The heaviest standard tissue paper option:
| Weight (LB/GSM) | Best For | Key Characteristics | Cost Level |
|---|---|---|---|
| 11lb/17g | Everyday items | Thin, soft, semi-transparent | $ |
| 15lb/22g | Premium retail | Medium strength, luxury feel | $$ |
| 20lb/30g | Heavier items | Thick, protective, opaque | $$$ |
| 30lb/45g | Luxury packaging | Maximum protection, substantial | $$$$ |
GSM and LB measure paper weight differently. GSM is metric. LB is imperial and depends on paper type.
Remember these key formulas:
Pick lighter weights for prints. Choose heavier ones for packaging or cards.
Know your paper type—Text or Cover—before converting.
Accurate conversions prevent printing issues and save time.
