ganak.appGSM Calculator
Free GSM calculator for fabric, paper and materials. Calculate grams per square meter from sample weight, find material weight from GSM, or compute roll weight. Converts GSM to oz/yd², lbs/ream and g/ft² with instant results and a material reference guide covering paper, fabric, towels and packaging.
Sample Measurements
Tip: Standard GSM cutter samples are 100 mm × 100 mm
Unit Conversions
Equivalent values in other measurement systems
GSM Reference Guide
Common GSM ranges by material type
What is GSM?
Understanding grams per square meter
GSM stands for Grams per Square Meter — the universal standard for measuring the weight (or "basis weight") of sheet materials. It tells you how much one square meter of a material weighs in grams. A higher GSM means a thicker, heavier material. GSM is used across industries including textiles, paper manufacturing, printing, packaging, and construction.
Paper & Printing
Copy paper (80 GSM), card stock (200+ GSM), tissue (15–30 GSM)
Textiles & Fabric
Chiffon (30–70 GSM), cotton (100–200 GSM), denim (300–450 GSM)
Towels & Linen
Pool towels (300–400 GSM), bath (400–600 GSM), luxury (600+ GSM)
How to Calculate GSM
The formula and step-by-step method
GSM Formula
GSM = Weight (g) ÷ Area (m²)
or equivalently: GSM = Weight (g) × 1,000,000 ÷ (Length mm × Width mm)
Cut a sample
Use a GSM cutter (100 mm × 100 mm is standard) or measure any rectangular piece with a ruler.
Weigh the sample
Use a digital scale accurate to at least 0.01 g. Record the weight in grams.
Measure dimensions
Record the length and width of your sample in millimeters, centimeters, or inches.
Calculate
Enter the values into the calculator above, or divide the weight by the area in square meters.
GSM vs Basis Weight (lbs/ream)
Understanding US paper weight standards
In the US, paper weight is often expressed as "basis weight" in pounds per ream (500 sheets). The confusing part: different paper types use different standard sheet sizes. A "20 lb bond" and "50 lb text" paper can have nearly the same GSM. Our calculator converts GSM to all three standard basis weights: Bond (17"×22"), Text/Offset (25"×38"), and Cover (20"×26").
| GSM | Bond (lb) | Text (lb) | Common Use |
|---|---|---|---|
| 75 g/m² | 20 lb | 50 lb | Copy paper |
| 90 g/m² | 24 lb | 60 lb | Letterhead |
| 120 g/m² | 32 lb | 80 lb | Premium stationery |
| 160 g/m² | 43 lb | 108 lb | Brochures |
| 250 g/m² | 67 lb | 169 lb | Business cards |
| 350 g/m² | 93 lb | 236 lb | Heavy card stock |
Common GSM Mistakes
Avoid these measurement errors
Frequently Asked Questions
Common questions about GSM, fabric weight, and paper weight calculations