Mil thickness is a unit of measurement commonly used in manufacturing to gauge the thickness of plastic films. One mil is equal to one thousandth of an inch (0.001 inches) or .0254 millimeters. Notice that mil thickness is not the same as millimeters, despite the similarity in name.

How is Mil Thickness Measured?

Mil thickness is typically measured using a micrometer or gauge designed specifically for measuring the thickness of plastic films. The device utilizes a controlled pressure on the film's surface to provide a precise measurement of thickness in mils.

Comparison to Objects

To put mil thickness into perspective, let’s compare it to a few familiar objects.

• Credit Card: The average credit card has a thickness of about 30 mils.
• Sandwich Bag: A sandwich bag is approximately 1 mil thick.
• Plastic Grocery Bag: A typical plastic grocery bag is around 2.25 mils thick.

Importance of Mil Thickness

Mil thickness directly impacts the strength, durability, and performance of tape in various applications.

Thicker tapes offer greater tear resistance and puncture protection for heavy-duty applications, while thinner tapes are more economical and suitable for general use. 

When deciding on the mil thickness right for you, consider the application and substrates associated with your project.