Not all canvas tote bags are created equal. Besides the size, types of pockets, construction of the bottom of the bag, and the types of straps; there is a weight measurement known as “grams per square meter” that is normally abbreviated as GSM.
This pertains to how thick the canvas material is and will go a long way in giving you a good idea of how much of a beating it can take; how tough the material of your canvas bag is. There more you stuff into it, especially bulky items with hard corners, the higher you’ll want the GSM to be.
Wait a Minute; Exactly What is Canvas?
Canvas is usually made from cotton or linen, with the linen being composed of the fibers from the flax plant. It normally has a plain weave with the vertical threads held tightly by a frame and the horizontal thread, as a continuous, unbroken thread, woven over-and-under the vertical threads. This simple pattern creates a very strong and durable fabric.
Canvas feels heavy and rough to the touch when it is brand new but is actually light in weight compared to other fabrics that are not as resistant to tearing. Along with bags and backpacks, the canvas is a tough material that is also used for martial arts uniforms, canopies, trampolines, tents, sails, and more.
How Do I Know What GSM I Need for My Canvas Bag?
The most popular weight is 100 GSM; however, this is popular for people who just want something to carry a few things with them once or twice a week. They’re not going to be stuffing a laptop and bulky items with hard corners that will want to tear the fabric of the bag.
If your canvas tote is going to experience daily use with a wide assortment of times being crammed inside it, consider a purchase of a bag made with the canvas that has a GSM of 150. It might feel very stiff and awkward when you first get it, but it the long run it will serve you well.
Ounce Weight and GSM
A lot of the time, you’ll find canvas weight presented not in the metric form of GSM, but in the form of the imperial unit of measure using ounces. To give you a rough guide; 100 GSM is equal to 3.5 ounces and 150 GSM is equal to 5.25 ounces.
One Last Question; What is Duck Canvas?
Duck Canvas has a tighter weave resulting in a higher thread count. This means that duck canvas is tougher, yet it will feel smoother to the touch. However, it is more expensive and could be more than you really need.