BUYER TOOLS · FREE TO USE
Sample grammage calculator
Cut, measure and weigh. Turn a sample of the complete finished material into grams per square metre.
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02 / FINISHED-MATERIAL GRAMMAGE
Mass per square metre
120 g/m²
Estimated from your measured samples
- Total sample area
- 0.03 m²
- Average mass per sample
- 1.2 g
Calculated precision is not measurement accuracy. This is arithmetic support, not a standardised laboratory acceptance test.
The formula
Total area (m²) = length (mm) × width (mm) × sample count ÷ 1,000,000
GSM = total net sample mass (g) ÷ total area (m²)
Example: three 100 × 100 mm samples cover 0.03 m². If they weigh 3.6 g together, grammage is 3.6 ÷ 0.03 = 120 g/m².
A 100 × 100 mm square covers 0.01 m²—not 0.1 m². A single sample’s mass in grams is therefore multiplied by 100 to obtain GSM.
Small samples amplify measuring errors
Measure the cut edges, not the intended cutter size. For example, a 1.2 g sample actually cut to 99 × 99 mm gives about 122.44 g/m², not 120.
Use an appropriate calibrated balance. Moisture, cut-size variation, uneven construction and scale resolution affect the result. Multiple samples can help represent a roll; this tool does not calculate a lab confidence interval.
Convert g/m² to oz/yd², or review the roll inspection guide.
About this video
How to use the free sample grammage calculator at www.leetaiheng.com/tools/gsm-calculator/. Enter the sample length and width in mm, the number of equal-sized samples and the total net mass of all samples in grams. Tare the weighing container first, weigh all entered samples together, keep all laminate layers together and count cut samples, not laminate layers. The formula: total area (m²) = length (mm) × width (mm) × sample count ÷ 1,000,000; GSM = total net sample mass (g) ÷ total area (m²). A 100 × 100 mm square covers 0.01 m², not 0.1 m². Example values only: three 100 × 100 mm samples cover 0.03 m²; if they weigh 3.6 g together, grammage is 120 g/m². Small samples amplify measuring errors, so measure the cut edges, not the intended cutter size: a 1.2 g sample actually cut to 99 × 99 mm gives about 122.44 g/m², not 120. Copy the calculation summary into your purchasing notes or inquiry. Calculations run in your browser. Example values are not a product specification, and the tool is arithmetic support, not a standardised laboratory acceptance test.
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