How to Measure Paper GSM Without a Professional Tester ?

How can I verify the paper GSM by myself?

Below is a simple, practical, and widely accepted method to measure paper grammage (GSM) using only basic tools. This method is especially useful for paper cups, cupstock paper, and packaging paper.

What Is GSM?

GSM (Grams per Square Meter) means the weight of paper per square meter.

• The heavier the GSM, the thicker and stronger the paper
• GSM is one of the most important indicators for paper cup quality

The formula is:

• GSM = weight of 1 square meter of paper (in grams)

Since 1 square meter is too large to measure directly, we use a 100 cm² paper sample instead.

Tools You Need

• A ruler
  
• Scissors or a cutter
  
• A digital scale (accuracy 0.01 g recommended)
  
• A flat working surface

Step 1: Cut a 100 cm² Square Sample

Cut a square paper sample with an area of 100 cm².

Common sizes:

• 10 cm × 10 cm
  
• 20 cm × 5 cm
  

Make sure the edges are straight and the size is accurate.

Step 2: If the Sample Is Too Big, Cut a Half Sample

Sometimes the full 100 cm² sample is too large to fit into the paper cup fan area or curved section.

In this case:

• Cut the 100 cm² square into two equal halves
  
• Each half = 50 cm²
  

This does not affect accuracy, as long as the cut is even.

Step 3: Put the Paper on the Cup Fan and Cut

Place the square (or half square) onto the paper cup fan or the exact material you want to test.

Cut the sample carefully so it matches the shape of the fan.

This ensures the tested paper truly represents the production material.

Step 4: Weigh the Paper Sample

Put the paper sample on a digital scale and record the weight.

Example:

• Weight of half sample (50 cm²) = 1.39 g

Step 5: Calculate the GSM

Formula

• 2 × half sample = 1 full square (100 cm²)
  
• GSM = weight of 100 cm² × 100
  

Example Calculation

• Half sample weight = 1.39 g
  
• Full square weight = 1.39 × 2 = 2.78 g
  
• GSM = 2.78 × 100 = 278 gsm
  

If the paper includes PE coating:

• PE coating weight = 18 gsm
  
• Base paper GSM = 278 − 18 = 260 gsm
  

✅ Final result: 260 gsm base paper

Notes for Better Accuracy

• Use a scale with 0.01 g precision
  
• Cut the paper cleanly and evenly
  
• Avoid touching the paper too much before weighing
  
• Test multiple samples and take the average if needed

Why This Method Is Widely Used

• Simple and low-cost
  
• No professional lab equipment required
  
• Accepted by most paper cup manufacturers and buyers

If you are sourcing paper cup raw material, PE-coated paper, or bamboo pulp cupstock, this method helps you quickly confirm GSM before production.

If you need help choosing the right GSM for your paper cups, feel free to contact us.