Ease and fit: why the same measurement gives different garments
What you take from this lesson: Be able to decide how much ease a garment needs based on how it will be used and what fabric it is made of.
Ease is what separates the body from the garment
If a garment measured exactly the same as the body, you couldn't even raise an arm. Ease is the difference between the body measurement and the measurement of the finished garment, and it is a design decision, not a calculation error.
Two garments made from the same size chart can be completely different just because of the ease they were given.
How much ease each garment needs
Approximate ease values over the bust circumference, in fabric without elastane:
- Very close fit (tank top, fitted t-shirt): 0 to 4 cm.
- Regular fit (classic t-shirt, shirt): 6 to 10 cm.
- Loose fit (sweatshirt, oversized shirt): 12 to 20 cm.
- Outerwear worn over other clothes: 20 to 30 cm.
The fabric changes the whole calculation
These values are for fabrics that don't stretch. If the fabric has elastane, the ease you need drops a lot, and in very stretchy garments it can even be negative: the garment measures less than the body and stretches when you put it on.
Leggings are the extreme example. If you drafted them with the ease of gabardine pants, they would fall down on their own. They are drafted with negative ease on purpose, counting on the knit fabric to stretch.
That is why a pattern is designed for one type of fabric, and switching fabrics without adjusting anything is the number one cause of garments that turn out different from what you expected.
Where fit shows up
Fit is not decided at the bust circumference, which is the measurement everyone looks at. It is decided in three less obvious places: where the shoulder seam falls, how deep the armhole is, and where the waist ends.
A garment with the right circumference but a shoulder that drops two centimeters too far looks wrong on the body even if the measurements check out. That is why the final test of a pattern is always the sewn garment worn on a body, not the measurement sheet.
In short
Ease is the difference between the body and the garment, and it is a design decision. It changes with how the garment is used and, above all, with how much the fabric stretches.
Frequently asked questions
- How much ease does a t-shirt need?
- In fabric without elastane, between 6 and 10 cm over the bust circumference for a regular fit. In jersey with elastane, quite a bit less.
- Can I use a pattern designed for stretch fabric on woven fabric?
- Not without adjusting it. A pattern for stretch fabric is drafted counting on the fabric to stretch; in woven fabric the garment comes out tight and sometimes simply doesn't fit over the body.