Calculate paper thickness in mm, microns, and inches from GSM and paper type. Know your stack height, pages per cm, and common applications.
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Per Sheet Thickness
0.100 mm
Millimeters
In Microns
100 µm
1 µm = 0.001 mm
In Inches
0.00394 in
1 mm = 0.03937 in
Total Stack Height
0.100 mm
For 1 sheet(s)
Pages Per cm
100
How many sheets make 1 cm
📌 Common Applications for This Paper
📝 Step-by-Step Calculation
Real-World Paper Thickness Examples
📄 Standard Office Paper (80 GSM Bond)
A typical 80 GSM bond/office paper has a caliper factor of approximately 0.10.
Calculation: 80 × 0.10 ÷ 1000 = 0.08 mm per sheet
In microns: 80 µm — In inches: ~0.00315 in
A 500-sheet ream: 500 × 0.08 = 40 mm (4 cm) thick
Commonly used for: printing documents, photocopying, letterheads, and general office use.
📰 Glossy Magazine Paper (100 GSM)
A 100 GSM glossy/magazine paper typically has a caliper factor around 0.085.
Calculation: 100 × 0.085 ÷ 1000 = 0.0085 mm per sheet
In microns: 85 µm — In inches: ~0.00335 in
Pages per cm: 10 ÷ 0.085 = ~118 pages/cm
Ideal for: magazine articles, brochures, catalogs, and high-quality color printing.
🎨 Cardstock (250 GSM)
A 250 GSM cardstock has a caliper factor of approximately 0.22.
Calculation: 250 × 0.22 ÷ 1000 = 0.055 mm per sheet
In microns: 55 µm — In inches: ~0.00217 in
A stack of 100 sheets: 100 × 0.055 = 5.5 mm thick
Perfect for: business cards, postcards, greeting cards, invitations, and scrapbooking.
📦 Kraft Corrugated Board (~600 GSM equivalent)
Heavy kraft/corrugated board at approximately 600 GSM with a caliper factor of 0.35.
Calculation: 600 × 0.35 ÷ 1000 = 0.21 mm per sheet
In microns: 210 µm — In inches: ~0.00827 in
Pages per cm: 10 ÷ 0.21 = ~48 sheets/cm
Used for: shipping boxes, packaging, cardboard mailers, and industrial wrapping.
💳 Cover Stock (350 GSM)
Heavy 350 GSM cover stock has a caliper factor of approximately 0.32.
Calculation: 350 × 0.32 ÷ 1000 = 0.112 mm per sheet
In microns: 112 µm — In inches: ~0.00441 in
A stack of 50 sheets: 50 × 0.112 = 5.6 mm thick
Great for: book covers, report covers, presentation folders, and premium packaging.
📖 Paper Thickness Reference Guide
Paper thickness varies widely depending on the paper type, weight (GSM), and manufacturing process. This guide provides typical caliper factors and thickness ranges for common paper types.
Standard Paper Types & Their Caliper Factors
Paper Type
GSM Range
Caliper Factor
Typical Thickness (mm)
Common Uses
Bond / Office
75–90
0.09–0.12
0.068–0.108
Printing, copying, letterhead
Glossy / Magazine
80–130
0.07–0.10
0.056–0.130
Magazines, brochures, catalogs
Cardstock
150–350
0.15–0.30
0.225–1.050
Business cards, postcards, invitations
Cover Stock
200–400
0.25–0.40
0.500–1.600
Book covers, presentation folders
Kraft / Corrugated
100–1000
0.15–0.50
0.150–5.000
Packaging, boxes, wrapping
Newsprint
40–55
0.08–0.12
0.032–0.066
Newspapers, flyers, drafts
Tissue Paper
15–35
0.05–0.09
0.008–0.032
Wrapping, crafts, delicate items
Thickness (mm) = GSM × Caliper Factor ÷ 1000
The caliper factor represents the thickness in millimeters per gram per square meter. Multiply by GSM, then divide by 1000 to get thickness in mm.
Thickness (µm) = Thickness (mm) × 1000
1 micron (µm) = 0.001 millimeter
Thickness (in) = Thickness (mm) × 0.03937
1 millimeter = 0.0393701 inches
Pages per cm = 10 ÷ Thickness (mm) per sheet
How many sheets are needed to reach 1 cm (10 mm) in stack height.
Understanding Paper Weight (GSM) vs. Thickness
GSM (grams per square meter) measures the weight of paper, not its thickness. Two papers with the same GSM can have different thicknesses due to differences in density, fiber composition, and manufacturing processes. This is why we use the caliper factor — it accounts for the paper's specific density to convert weight into thickness.
For example, a 100 GSM bond paper (caliper ~0.10) will be thicker than a 100 GSM glossy paper (caliper ~0.085) because the glossy paper is denser and more compressed.
How to Measure Paper Thickness
1
Use a micrometer or caliper: A precision measuring tool that can measure down to 0.01 mm or finer.
2
Measure a stack: For thin papers, measure 10–100 sheets together and divide by the number of sheets for accuracy.
3
Multiple measurements: Take readings at different spots and average them for consistent results.
4
Use the calculator: Enter your measured values to find the caliper factor or use our presets for standard papers.
Quick Tips for Working with Paper Thickness
📏 Know Your Printer Limits
Most home printers can handle up to 120 GSM (bond paper). For cardstock or cover stock, check your printer's maximum paper weight specification.
📮 Postage Matters
Heavier paper increases mailing costs. A standard business card (350 GSM) weighs about 5–7 times more than a standard letter sheet (80 GSM).
📚 Binding Considerations
A book's spine width depends on total paper thickness. For perfect binding, add ~2–3 mm for glue. For 200 pages of 80 GSM bond (~0.08 mm each), the spine is about 16 mm.
🖨️ Double-Sided Printing
Thicker papers (above 120 GSM) may not feed well for automatic duplex (double-sided) printing. Check your printer's duplex specifications before buying heavy paper.
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Multi-Unit Results
Get paper thickness in millimeters, microns, and inches simultaneously. No manual conversions needed.
📚
Stack Height Calculator
Know exactly how thick a stack of any number of sheets will be — perfect for binding, packaging, and storage planning.
📋
Paper Type Presets
Choose from bond, glossy, cardstock, cover, and kraft presets with pre-filled caliper factors for quick calculations.
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Common Applications
See practical uses for your selected paper type and thickness — from office documents to premium packaging.
Paper thickness, also called paper caliper, is the distance between the top and bottom surfaces of a single sheet of paper. It is typically measured in millimeters (mm) or microns (µm). Unlike paper weight (GSM), which measures mass per unit area, thickness directly tells you how much physical space the paper occupies.
Understanding paper thickness is crucial for many applications. Printers have maximum paper thickness specifications, binding machines need to know spine width, and packaging engineers need precise dimensions for boxes and envelopes. Our calculator bridges the gap between GSM (weight) and actual physical thickness.
GSM vs. Thickness — What's the Difference?
GSM (grams per square meter) measures how heavy a sheet of paper is. Two papers with identical GSM can have different thicknesses based on their density. For example, a 100 GSM coated glossy paper is thinner than a 100 GSM uncoated bond paper because the coating fills in the fibers, making it denser. The caliper factor accounts for this density difference, allowing accurate conversion from weight to thickness.
Why Paper Thickness Matters
🖨️ Printer Compatibility
Exceeding your printer's maximum paper thickness can cause jams, poor print quality, or damage to the printer mechanism.
📬 Mailing & Postage
Postal services charge based on weight and thickness. A thick stack may require extra postage or may not fit standard envelopes.
📕 Book Binding
Knowing total paper thickness is essential for choosing the right binding method and calculating spine width for book covers.
📦 Packaging Design
Corrugated board thickness determines stacking strength and protection levels for shipping containers and product packaging.
Frequently Asked Questions
What is the difference between GSM and paper thickness?
GSM (grams per square meter) is a measure of weight, not thickness. It tells you how much a square meter of paper weighs. Paper thickness (caliper) is the actual physical dimension of the paper. Two papers with the same GSM can have different thicknesses if they have different densities. For example, a coated glossy paper is denser than an uncoated bond paper, so it will be thinner at the same GSM. Our calculator uses the caliper factor to convert between these two measurements.
How do I find the caliper factor for my paper?
The caliper factor is typically provided by the paper manufacturer on the product specification sheet. If you don't have this information, you can measure it: (1) measure the thickness of a stack of 100 sheets with a micrometer or caliper, (2) divide by 100 to get the thickness per sheet in mm, (3) divide by the GSM and multiply by 1000 to get the caliper factor. For standard papers, you can use our preset values which are typical industry averages.
What GSM paper should I use for printing?
For everyday office printing, 80–90 GSM bond paper is standard. For presentations and reports, 100–120 GSM provides a more professional feel. 150–200 GSM is good for flyers and brochures, while 250–350 GSM is ideal for business cards and postcards. Always check your printer's specifications — most home printers can handle up to 120 GSM, while professional printers can handle up to 400 GSM.
How many pages fit in a 1 cm stack?
The number of pages per cm depends on the paper thickness. For 80 GSM bond paper (~0.08 mm thick), approximately 125 sheets make 1 cm. For 100 GSM glossy paper (~0.085 mm), about 118 sheets. For 250 GSM cardstock (~0.055 mm), around 182 sheets. Our calculator computes this automatically based on your paper type and GSM.
What does "20 lb paper" mean in GSM?
In the US, paper weight is often measured in pounds (lb) based on the weight of a ream (500 sheets) of a standard size. 20 lb bond paper is approximately 75 GSM, 24 lb is about 90 GSM, and 28 lb is roughly 105 GSM. The conversion varies by paper type (bond, cover, index) because the base sheet sizes differ. Our calculator uses GSM directly, which is the international standard.
Can I use the same caliper factor for all papers of the same type?
Caliper factors are approximate averages and can vary between manufacturers, paper brands, and even production batches. Coated papers (like glossy magazine paper) tend to have lower caliper factors (more dense), while uncoated papers (like bond) have higher caliper factors. Always use the manufacturer's specified caliper factor for the most accurate results. Our presets provide good estimates for common paper types.
⚠️ Important Note: This Paper Thickness Calculator provides estimates based on typical caliper factors. Actual paper thickness can vary by manufacturer, production batch, and environmental conditions (humidity affects paper thickness). For critical applications such as book binding, packaging design, or printer specifications, always verify with the actual paper or manufacturer-provided specifications.