Lightweight jersey is the go-to fabric for summer t-shirts, inner layers, and fast-fashion basics. At 140–150 grams per square meter, it's the lightest knit you'll commonly find in apparel production — breathable, soft to the touch, and quick to dry.
If you've ever worn a thin, breezy t-shirt on a hot day, that was probably lightweight jersey. The low GSM (grams per square meter) means less material per unit area — which translates to a more transparent fabric, lower cost per meter, and a silhouette that drapes close to the body.
Use lightweight jersey when you need breathability and low cost. Avoid it when you want opacity, structure, or a premium hand feel.
What does GSM actually mean?
GSM stands for grams per square meter — the standard unit for measuring fabric weight in apparel. A higher GSM means a denser, heavier fabric. A lower GSM means lighter, more open construction.
For jersey knits, the typical range goes from about 120 g/m² (very sheer) up to 300+ g/m² (thick sweatshirt territory). Lightweight jersey sits at the lower end of that range: breathable enough for summer, but substantial enough to hold a basic garment shape.
How lightweight jersey compares to other jerseys
Production specs for your tech pack
When you specify lightweight jersey in a tech pack or Bill of Materials (BOM), these are the values your factory and fabric supplier will need:
| Spec | Value | Notes |
|---|---|---|
| Fabric type | Single jersey knit | Machine knitted, not woven |
| Weight (GSM) | 140–150 g/m² | Specify a tolerance of ±5 g/m² |
| Fiber content | 100% Cotton | Combed or ring-spun preferred |
| Shrinkage | Max 5% after wash | Sanforized finish recommended |
| Dyeing method | Piece dyed (reactive) | For solid colors |
| Color standard | Pantone TCX | Textile Cotton eXtended palette |
In FlatLabs PRO, when you select Lightweight Jersey in the Fabric step, these specs are automatically added to your Bill of Materials and spec sheet PDF — including fiber content, GSM, and care label requirements (EN ISO 3758).
No copy-pasting from reference sheets. The tech pack fills itself.
When to use it — and when not to
Good for: Summer basics, graphic tees in lighter colorways, inner layers for multi-piece looks, fast-fashion production runs where cost per unit matters, and any design where drape and breathability take priority over structure.
Avoid when: You want opacity in white or light colors (lightweight jersey tends to be slightly sheer), when the garment needs to hold a structured silhouette on its own, or when you're targeting a premium market where hand feel and weight are part of the value proposition.
For most quality t-shirt brands, midweight jersey at 180 g/m² is the default. Lightweight is a deliberate choice, not a starting point.
A note on sheerness
The most common surprise with lightweight jersey in production: the final garment is more transparent than expected, especially in white or very light colors.
This isn't a manufacturing defect — it's physics. Less fiber per square meter means more light passes through. If your design spec calls for lightweight jersey in white, it's worth noting "opacity: sheer acceptable" or "opacity: add liner" in your construction notes, so your factory knows the intent and doesn't flag it as a quality issue.