What is gsm.
GSM is grams per square metre, the weight of a paper, board or fabric. Every bag spec on this site gives one. This page explains what the number measures, what it does not, and which weight suits which bag.
The short answerGSM stands for grams per square metre. It is the weight of one square metre of paper, board or fabric, defined for paper in ISO 536. A higher gsm means more material in every square metre.
Weight, not thickness
GSM measures mass, not thickness. Paper thickness is measured on its own, under ISO 534, and two papers of the same gsm can differ in thickness.
A dense, pressed paper such as glassine feels thin for its weight. A bulky uncoated paper feels thicker at the same gsm.
GSM and US pound weights
In the US, paper is sold by basis weight in pounds, and the pounds depend on the paper type. That makes gsm the easier number to compare.
| US paper weight | In gsm |
|---|---|
| 20 lb bond | about 75 |
| 80 lb text | about 118 |
| 80 lb cover | about 216 |
To convert, multiply bond weights by 3.76, text by 1.48 and cover by 2.70.
GSM on our bags
| Bag | Material | Weight |
|---|---|---|
| Food grade bag | Greaseproof paper | 35 to 50gsm |
| SOS paper bag | Kraft paper | 70 to 100gsm |
| Kraft paper bag | Kraft paper | 80 to 270gsm |
| Laminated paper bag | Coated art paper | 128 to 250gsm |
| Cotton bag | Cotton canvas | 100 to 320gsm |
| Non-woven bag | Non-woven polypropylene | 80 to 180gsm |
| Insulated tote bag | Non-woven fabric | 70 to 100gsm |
Film is measured differently. Pouches are given in millimetres, 0.10 to 0.12mm, and compostable carriers in microns, 18 to 25.
Heavier is not always better. A 35gsm greaseproof bag folds around a croissant, and a 270gsm kraft bag with rope handles carries a boxed gift. Tell us what goes in and we match the weight.
Questions
What does gsm mean?
Grams per square metre. It is the weight of one square metre of paper, board or fabric.
Is higher gsm thicker?
Not always. GSM measures weight. Thickness is measured separately, and a dense paper can be heavier and thinner than a bulky one.
What does gsm mean for fabric?
The same thing: the weight of one square metre. Our cotton bags run from 100 to 320gsm, and the heavier canvas holds its shape and carries more.
What gsm is good for a paper carrier bag?
It depends on the load. Our kraft bags run from 80gsm for takeaway to 270gsm for heavy retail with rope handles. Tell us what goes in and we match the weight.
How do I convert pounds to gsm?
Multiply by 3.76 for bond, 1.48 for text and 2.70 for cover. A 20 lb bond paper is about 75gsm.
Written by the Bag Bureau production team. Last updated October 2026.