Paper thickness is a crucial characteristic of printer paper that impacts its durability, feel, and quality. While paper weight is used to describe the mass of paper, caliper (the actual thickness) gives a more accurate measure of how thick the paper feels. Understanding the relationship between paper size, weight, and thickness is imperative when you need to decide which printer paper type you should use.
Definition: Paper thickness
Paper thickness, which is known as caliper, refers to the physical dimensions of a single sheet of paper. This can be measured with either a micrometer or a thickness gauge. A paper caliper can be expressed in three units:
- Microns (µm) – 1 micron equals 0.001 mm; used internationally
- Points (pt) – 1 point equals 0.001 inches; measures paperboard & cardstock
- Mils – 1 mil equals 0.001 inches; used for plastics & films
The relationship between paper thickness and weight is direct, as thicker papers are generally heavier. However, paper thickness can vary based on material and paper coating, meaning that a paper’s weight only offers a rough estimate of its thickness.
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Microns vs. points vs. mils
It might be confusing as to why there are three units of measurement when it comes to paper thickness. In this section, we’ll explain the differences between microns, points, and mils.
| Unit | Micron | Point | Mil |
|---|---|---|---|
| Region | International standard | North America | North America |
| Abbreviation | μm | pt | mil |
| Usage | Paper, plastic film, coatings | Paperboard, cardstock | Plastic film, coatings, metals |
| Measurement system | Metric | Imperial | Imperial |
Conversion calculator
Understanding how to convert between microns, points, and mils is essential when dealing with paper and material thickness in different regions. Below, we give you the conversion formula of each unit.
Convert to microns
1 mil/point is equal to 25.4 microns. This means that if you know the thickness in mils/points, you can convert to microns by multiplying it by 25.4.
mils/points × 25.4 = microns
Example
A typical office paper (20 lb) is around 3.8 pt (0.0038 in) thick.
→ 3.8 pt × 25.4 = 96.52 µm
Convert to points
To convert microns to points, you need to divide microns by 25.4.
microns ÷ 25.4 = points
Example
A typical office paper (80 gsm) is around 100 µm (0.1 mm) thick.
→ 100 µm ÷ 25.4 = 3.94 pt
Click on the button below to try out a conversion calculator.
Thickness of paper types
Each type of paper has a specific thickness range depending on its intended use. From every document printing to premium photo printing, different applications require different paper thicknesses to perform optimally.
Copy paper
- Used for everyday office tasks
- Thickness range: 70–120 µm (approx. 2–4 pt)
- Lightweight paper for easy handling in standard printers
Medium cardstock
- Suitable for brochures, postcards, covers & invitations
- Thickness range: 150–250 µm (approx. 6–10 pt)
- Ideal for professional documents, e.g., for certificate printing
Heavy cardstock
- Best for business cards, packaging & durable covers
- Thickness range: 290–400 µm (approx. 11–16 pt)
- Offers a sturdy feel for professional & luxury applications
FAQs
Standard copy paper is typically 70–100 microns thick (about 2–4 pt) and weighs 80–90 gsm or 20–24 lb in the US system.
Yes, 200 gsm paper is considered thick for general printing and is often used for brochure covers and premium flyers.
20 lb paper is standard for lightweight printing, while 24 lb Is often used for letterheads and formal documents to convey higher quality. The higher the number, the thicker the paper.
Thick paper is commonly referred to as a cardstock or cover stock.
You can tell paper thickness by:
- Weight (gsm or lb)
- Caliper (microns or points)
- Feel & stiffness
- Application, e.g., business cards
