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When it comes to specifying paperboard, one small number makes a big impact: caliper. Whether you're producing folding cartons, displays, or rigid boxes, the thickness of your paperboard directly affects its strength, appearance, and how it performs in your equipment.
What Is Caliper?
Caliper refers to the thickness of paperboard, and it’s one of the most important specifications for any packaging or print project.
In the U.S., caliper is typically expressed in points, where: - 1 point = 0.001 inch.
So, a 98pt board, for example, measures 0.098 inches thick. In metric, caliper is expressed in microns, with: - 1,000 microns = 1 millimeter.
At Lamitech, we measure caliper using a precision micrometer, following TAPPI Test Method T411. This standardized method ensures consistency across all grades, including standard or laminated boards.
What Is a Point?
The term “point” is commonly used when referring to thicker papers and paperboards, such as:
- 10PT (.010”)
- 12PT (.012”)
- 14PT (.014”)
- 20PT (.020”), and so on.
The higher the point number, the thicker and often more rigid the board. It’s a simple way to quickly convey the material's thickness.
What Is a Mil?
Occasionally, caliper is also expressed in Mils, particularly in plastic films or laminates.
Like points, 1 Mil = 1/1000th of an inch (.001”), but Mils are typically used when referring to coatings or finishes—for example:
- A 1.5 Mil laminate equals .0015 inches
- A 5 Mil laminate equals .005 inches
Some assume “Mil” is short for millimeter, but it's derived from the French word 'mille', meaning one thousand.
What Tolerance Can You Expect?
In paperboard manufacturing, slight variations are normal. The industry standard allows for a ±5% caliper tolerance, meaning a 20pt board might range from 0.019" to 0.021". This margin ensures efficient production while maintaining the board’s overall performance characteristics.
Why It Matters
The right caliper ensures your board runs smoothly through your converting equipment, folds properly, holds its shape, and looks professional. Choosing the wrong caliper can lead to cracking, warping, or worse, customer dissatisfaction.
At Lamitech, we stock and convert a wide range of calipers to meet the needs of our customers in packaging, printing, signs, displays, and more.
Contact Us
Have questions about the right caliper for your project?
📞 Call us at (609) 860-8037 or ✉️ Contact us at [email protected].
We’re happy to help you choose the best board for your application.
