Start with what the legging has to do
Before comparing fabrics, write one sentence about the customer and the practice. A legging for heated vinyasa classes has a different job from a legging for slow flow, pilates reformer work or wearing all day. The first needs to move sweat and stay opaque when wet. The second needs softness and a gentle hold. The third needs a waistband that stays put during rolling and a seat that stays opaque in deep flexion.
Once the job is written down, the fabric decision becomes a short list of measurable properties: fiber, spandex share, weight, knit structure and finish. Those five items belong on the fabric sheet that the partner mill confirms before the first sample.
Fiber: nylon or polyester
Most performance yoga leggings use a nylon and spandex blend. Nylon has a smooth, cool hand, good abrasion resistance and a soft drape, which is why it dominates premium leggings. Polyester and spandex blends cost less, hold color well and are the usual base for sublimation printing, but they tend to feel slightly less soft and can hold odor more readily.
| Property | Nylon / spandex | Polyester / spandex |
|---|---|---|
| Hand feel | Smooth, cool, soft drape | Slightly crisper, sporty |
| Typical use | Studio and premium leggings, bras, sets | Printed styles, gym crossover, value lines |
| Printing | Usually solid dyed | Good base for sublimation prints |
| Cost position | Higher | Lower |
Neither is wrong. A brand with a studio customer and solid colors usually starts with nylon. A brand that sells bold prints or targets a lower retail price often starts with polyester. Our nylon vs polyester note goes deeper.
Spandex share: how much stretch and hold
For interlock leggings the common range is about 75-80% nylon and 20-25% spandex. Around 15% spandex reads as comfortable stretch. At 25% and above the fabric starts to feel compressive and supportive. The trap is a heavy fabric with only 8-10% spandex: it can look substantial on paper and feel stiff and boardy in a forward fold.
Spandex share also affects recovery, which is how well the fabric returns to shape after stretching. Recovery is what keeps knees from bagging after a class. Ask for stretch and recovery results on the fabric sheet, tested to a knitted-fabric method such as ASTM D2594. See stretch and recovery testing.
Weight: GSM and opacity
Fabric weight is stated in grams per square meter. Most premium performance leggings sit between 230 and 280 GSM. Weight matters mostly because of opacity, the property buyers lose sleep over. Dark colors may pass a deep squat at 230-240 GSM; white and pastel colors often need 280-300 GSM in the same construction, because there is no dye depth to hide the skin underneath.
Two more details belong on the sheet. First, GSM has a tolerance, typically around plus or minus 5% of the nominal weight, measured to ISO 3801 or ASTM D3776. Second, brushing a fabric can add 5-15 GSM, so ask for both the base and the finished weight when comparing a brushed and an unbrushed option. Our GSM guide covers bras and tops as well.
Knit structure: interlock, jersey or seamless
Interlock is a double knit with the same face on both sides. It is stable, opaque for its weight and does not curl at cut edges, which is why it is the standard for cut and sew leggings. Single jersey is lighter and more prone to curling and see-through. Seamless leggings are knitted as a tube on circular machines, with rib or compression zones built in; their opacity and hand depend on yarn and knit program rather than on a fabric roll specification. If you are deciding between the two routes, read seamless vs cut and sew.
Finish: brushed, smooth or textured
A brushed or peached finish raises fibers on the face and creates the soft, almost suede-like hand that many studio customers like. It usually feels warmer and can pill more easily if the base fabric is not suited to brushing. A smooth, unbrushed face feels cooler and more technical and suits hot classes. Textures such as ribbing are usually a seamless feature. Pilling resistance should be tested on the finished fabric, not the base, to a method such as ASTM D4970 or ISO 12945-2.
Putting it on the fabric sheet
| Field | What to write |
|---|---|
| Composition | Fiber percentages, e.g. nylon / spandex share as confirmed by the mill |
| Weight | Base and finished GSM with tolerance |
| Structure | Interlock, jersey, rib or seamless program reference |
| Finish | Brushed or smooth; any wicking or anti-odor finish and how it is verified |
| Performance | Opacity check method, stretch and recovery, pilling, colorfastness to washing and perspiration |
| Colors | Color standards and the lightest color for opacity approval |
With this sheet signed off, sample comments can focus on fit instead of arguments about how the fabric feels. It also gives you a reference for reorders, so the second production run matches the first.
Colorfastness and care belong in the same decision
Leggings are washed often and worn against sweat, so color loss shows quickly at the seat and inner thigh. Ask for colorfastness to laundering, for example AATCC 61, and to perspiration, for example AATCC 15 or ISO 105-E04, on the actual dyed fabric. A grade of 3-4 is a common acceptance level for perspiration. Then write care instructions that match the test conditions, so the label tells customers to wash the way the fabric was approved.
Three common starting points
- Studio staple, solid colors: nylon / spandex interlock in the 230-260 GSM area, smooth or lightly brushed, dark and mid colors first.
- Soft-touch everyday legging: brushed nylon / spandex around 230-260 GSM finished, with pilling tested after brushing.
- Printed or value line: polyester / spandex in the 230-280 GSM range, with opacity checked on the lightest printed ground.
These are starting points for a conversation, not a recipe. The mill confirms what it can supply, and the partner factory confirms how the fabric behaves in your pattern. Browse the fabric library or the leggings guide, and when you have a shortlist, send it to the desk with your reference styles.