This Encyclopedia entry is a must-know term. Learn more in our Denim vocabulary.
Denim is measured in weight of ounces per square yard. It’s usually abbreviated as ‘oz’ or ‘oz.’ in writing.
This unit of mass is used to categorise denim fabric by weight. The higher the ounces, the heavier the denim.
The weight of denim matters because it influences how the garment feels to wear and how durable it is.
Denim weight explained in more detail
Denim fabrics can have different weights because the yarn can have different thicknesses. This is also known as ‘yarn count.’
Quite simply, thick yarn weighs more. And the closer you pack it together, the more weight you cram into a square yard of the fabric.
Interestingly though, there’s no universal standard for denim weight categories. Brands that predominantly sell 10-12 oz. denim might consider 14 oz. heavy, while others might see 14 oz. as a lightweight.
Still, most agree on the following categorisation of denim weights:
- Less than 12 oz. = lightweight
- 12-16 oz. = midweight
- Above 16 oz. = heavyweight
So if your jeans are made from denim that’s more than 16 oz., you can rightfully call them heavyweight.
And that’s where you might say, ‘wait a minute, what’s ounces?!’ (That’s a totally legitimate question for all of us living in places where we’re blessed with the metric system.)
1 ounce equals 28.35 grammes. So 21 oz., for instance, is 595.34 grammes. But that doesn’t mean that all jeans made from 21 oz. weigh that, obviously.
When we talk about denim, it’s the weight of 1 square yard of that fabric we’re talking about. In ounces. 1 square yard is 0.84 square metres.
If you want to know how much your jeans weigh, you multiply the ounces per square yard with the number of square yards you need to make a pair of jeans, on average that is around 1.5 square yards.
And here it gets even more complicated and possibly confusing, because if the denim is woven on shuttle looms – in other words if it’s selvedge – the roll of fabric won’t be 1 yard wide; it will only be around 30 inches, or around 75 centimetres. That means you’ll need around 2 yards of fabric from the roll, but it’s still roughly 1.5 square yards.
That means those 21 oz. jeans will be around 31.5 oz or 890 grammes. Of course, this also all depends on the tag size of the jeans, the length of the legs, if they’ve been repair of if so how.
While it may be confusing to some of us, ounces per square yard (oz./yd2) is the standard in the denim industry, so you just have to learn it! (If you do insist on converting the oz./yd2 of your jeans to gsm, this tool is handy!)