Thermal Paper 101: GSM and Thickness

Thermal paper today can vary in different sizes and different qualities in order to satisfy different customers’ needs. That’s why when it comes to choosing the right type of thermal paper, one must have adequate knowledge about the basic properties it possesses. In layman’s terms, those properties in relation to thermal paper are called parameters. This article will discuss the two basic parameters of thermal paper – GSM and thickness, and how they are interconnected.

What’s the GSM of Thermal Paper?

GSM (Gram per Square Meter), or grammage, is used to describe the weight of one square meter of paper in the metric system according to the ISO 536:2019 Paper and Board standard. Its unit is GSM. In other words, you can calculate the GSM of a paper by simply taking one square meter of paper sample and then measuring its weight; that weight value is its GSM.

What’s the Difference Between GSM and Basis Weight?

You may also see “basis weight” on some industry websites, but what is the difference between GSM and basis weight? Basis weight (also known as paper weight) is an old-fashioned parameter mainly used in America and Canada. It refers to the weight of a ream (500 sheets) of given paper in its basic size. The basis weight is usually expressed in pounds and is calculated by weighing 500 sheets of paper in that standard size. For example, for A4 copy paper, you can measure a ream of 500 sheets of paper in its standard size (which is A4), then the weight value of those 500 sheets becomes the paper’s basis weight in pounds.

Because different types of paper have different basic sizes, basis weight can be confusing and inconsistent, so it is rarely used now and has been gradually abandoned by the industry. GSM, on the other hand, is straightforward, consistent, and much easier to evaluate paper quality. It is a universal standard used across Asia, Europe, and most of the world.

What Are the Common GSMs of Thermal Paper?

Here are the common GSMs of thermal paper in the market:

• 48 gsm
• 55 gsm
• 60 gsm
• 65 gsm
• 70 gsm

One thing often overlooked is that many people assume each GSM corresponds to a fixed thickness, but this is a misconception. Papers with the same GSM can still vary in thickness. This will be explained further in the next section.

What’s the Thickness of Thermal Paper?

Thickness, also called caliper, is measured in microns (μm). The measurement is taken with an instrument called a micrometer or thickness gauge, in accordance with the ISO 534:2011 standard. (If you want to purchase a micrometer from us, just get in touch.)

Normally, the caliper of paper should not vary by more than ±5% within the same sheet, as there are high spots and low spots on a sheet of paper. In general, the higher the caliper, the thicker and usually heavier the paper will be. However, the caliper of thermal paper can change noticeably due to several factors, including the raw materials used, the manufacturing process, the bulkiness of the paper, and the type of coating. This is why a higher GSM does not always mean a higher thickness.

What’s The Relationship Between Thermal Paper GSM and Thickness?

That said, it is still possible to estimate the thickness of thermal paper based on its GSM. Here are some common thermal paper GSMs and their corresponding thicknesses.

Make the Right Choice When Ordering Thermal Paper

Now that you understand the basic parameters of the thermal paper industry – GSM and thickness – you can see that they are the two main factors that affect a paper’s grade and price. By having a general idea of a thermal paper’s GSM and thickness, any business owner looking to source thermal paper rolls can more easily choose the right options that will satisfy their customers. If you still have questions about thermal paper, do not hesitate to contact the experts at Panda Paper Roll.