Muslin vs Canvas vs Calico: Cotton Bag Fabrics and GSM Explained
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Muslin, calico and canvas are the same fibre at three different weights. There is no separate plant and no different manufacturing process worth caring about — just how tightly the cotton is woven and how much of it there is per square metre. That number is GSM, and it predicts almost everything about how a bag will behave.
What GSM means
Grams per square metre — the weight of the fabric. Higher GSM means more cotton, a tighter weave, and a fabric that is more opaque, stronger and stiffer. Lower GSM means lighter, more breathable, more translucent and cheaper.
It is the single most useful number when comparing suppliers, and the one cheap listings most often leave out. Treat an unstated GSM as a warning sign.
The three side by side
| Muslin | Calico | Canvas | |
|---|---|---|---|
| Weight | Lightest | Mid (around 145 GSM) | Heaviest (250+ GSM) |
| Weave | Open, slightly translucent | Plain, opaque | Tight, dense |
| Breathability | High | Moderate | Low |
| Strength | Light loads | Everyday carry | Heavy loads, abrasion |
| Holds shape empty | No | No | Yes |
| Print detail | Ink spreads slightly | Crisp | Crisp, visible texture |
| Cost per bag | Lowest | Middle | Highest |
Muslin
The lightest and most open. You can see through it slightly, which is the specification rather than a fault. Its whole advantage is airflow — aroma and moisture pass through, which is why it is used for tea, herbs, spices, straining, soap and seed saving.
Its limits follow from the same property: it will not conceal contents, will not carry weight, and fine print detail spreads into the weave. See the complete muslin buyer's guide.
Calico
Plain-weave, unbleached, around 145 GSM. In practice this is what most people mean by "a cotton bag": opaque enough to hide the contents, strong enough for everyday carry, cheap enough to buy in volume, and crisp enough to hold a detailed print.
If you are unsure which to specify, this is almost always the right default. It is the standard across packaging, retail, promotional and gift use for good reason.
Canvas
Tight and heavy — 250 GSM and up. It stands upright when empty, resists abrasion, and carries real weight without stretching. Right for shoe bags, tool bags, grocery totes, premium retail and anything that must hold its shape on a shelf.
Two costs to weigh. It is more expensive per bag, and it is heavier to ship — so specifying canvas across a large run costs you twice. And it breathes far less, which actively works against coffee, bread, herbs and cured meat. More in canvas drawstring bags: when heavy-duty cotton beats muslin.
Choosing in one question
What does the bag need to do that the fabric decides?
- Let air through — muslin. Tea, herbs, spices, straining, seed, soap, produce.
- Hide the contents and take a clean print — calico at 145 GSM. Retail packaging, gifts, promotional bags, most things.
- Hold shape or carry weight — canvas. Shoes, tools, groceries, premium gifting, storage.
If more than one applies, the deciding factor is usually whether airflow matters. Nothing else about a cotton bag is as hard to work around.
What about bleached white?
A separate axis from weight. White cotton is any of these weights, bleached. It gives maximum print contrast and better batch consistency, at higher cost and with an extra chemical process. Natural unbleached is cheaper, hides marks better and carries the sustainability story. See white vs natural cotton.
Ordering
Browse muslin bags, the standard cotton drawstring bag range, or heavy canvas drawstring bags. All are GOTS certified organic and AZO-free. For branded runs from 100 pieces, custom drawstring bags with your logo.
Frequently asked questions
What is the difference between muslin, calico and canvas?
Weight and weave density — they are all cotton. Muslin is lightest and most open, calico is mid-weight at around 145 GSM and opaque, canvas is heaviest at 250 GSM and up and holds its shape.
What GSM should I choose?
145 GSM covers most uses: opaque, durable, prints cleanly and cheap to ship. Go lighter only when airflow is the point, and heavier only when the bag must hold shape or carry weight — heavier fabric costs more per bag and more in freight.
Is calico the same as cotton?
Calico is cotton — specifically unbleached plain-weave cotton at a mid weight. When people say "a cotton bag" without qualifying it, calico at around 145 GSM is usually what they mean.
Which is best for food packaging?
Muslin or 145 GSM cotton, depending on whether airflow helps. Coffee, bread, herbs and cured meat need to breathe, so use an open weave. For dry goods that just need containing, 145 GSM is fine. Avoid canvas, which restricts airflow.
Why does GSM matter for shipping cost?
Freight scales with weight, so a heavier fabric costs more per bag and more to deliver. On a large order, over-specifying the weight moves more money than the print does.
Not sure which weight you need?
Tell us what goes in the bag and how it will be used. We will recommend the fabric honestly and quote it.
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