Fabric weight describes how heavy a fabric is relative to its size. It is usually measured in grams per square metre (GSM), which indicates the weight of one square metre of cloth. This measurement helps compare fabrics and understand how they may behave in different applications.
Weight plays an important role in how a fabric feels, how it drapes and how it performs in use. Lighter fabrics tend to feel airy and fluid, while heavier fabrics provide greater structure and durability. In interior textiles, fabric weight often helps determine whether a cloth is suitable for curtains, upholstery or decorative soft furnishings.
What GSM means
GSM stands for grams per square metre. The higher the GSM number, the heavier the fabric.
For example:
- 150 gsm fabric is relatively lightweight
- 250 gsm fabric sits in a midweight range
- 400 gsm and above is typically considered heavyweight
This measurement does not describe thickness directly, but it provides a useful indication of the density of the yarns and the overall substance of the cloth.
Many fabric suppliers include GSM in their specifications so designers and makers can compare textiles more easily. People often ask what GSM is best for upholstery or what GSM works for curtains — weight is a useful starting point, alongside weave and finish
Typical fabric weight ranges
These ranges become more useful when you connect them to the kinds of fabrics people recognise.
Lightweight (100–200 gsm) often includes voile-like sheers, fine plain weaves, lightweight linen-style cloths, and some shirt-weight cottons. In interiors, these are most often chosen for light-filtering curtains, linings, or soft layering where drape matters more than durability.
Midweight (200–350 gsm) includes many classic interior fabrics: robust curtain linens, heavier plain weaves, twills, and textured cloths used for cushions, table linens, and general soft furnishings. This is also the range where decorative or occasional upholstery can sit — for example on a bedroom chair, a headboard, or panels that won’t see constant abrasion.
Heavyweight (350–600 gsm) is where you tend to find upholstery canvases, dense twills, heavy basket weaves, and other structured cloths designed to hold their shape and tolerate regular use. These fabrics typically feel more substantial in the hand, with a firmer “body” that helps them sit smoothly across furniture.
For practical selection, it helps to pair GSM with the application: lighter weights for a softer, airier curtain effect; heavier weights for furniture that needs structure and durability. You can explore examples in our guides to Hemp Fabrics for Curtains and Hemp for Upholstery.
Weight and fabric behaviour
Although weight provides useful information, it does not determine everything about how a fabric behaves.
Several other factors influence performance:
- fibre type
- yarn thickness
- weave structure
- finishing processes
This is why two fabrics with a similar GSM can feel and perform very differently.
A tightly woven midweight fabric may feel crisp, stable and quite structured, particularly if the yarns are firm and the finish is not heavily softened. A midweight twill, on the other hand, may drape more fluidly because the weave structure allows the cloth to flex. Likewise, a heavyweight canvas can feel very firm and architectural, while a heavyweight cloth with a looser weave may feel softer and more pliable.
Finishing also matters. Pre-shrinking treatments (such as sanforising) can stabilise a fabric, while mechanical softening or tumbling can increase suppleness and drape without necessarily changing the GSM. Dyeing and washing processes can alter handle too, which is why a fabric’s “feel” can’t be predicted by weight alone.
Because of this, fabric weight should always be considered alongside other characteristics such as texture, strength and drape — especially for interior projects where both appearance and performance matter.
To understand how fabrics hang and move, see Understanding Fabric Drape.
Weight and natural fibres
Different natural fibres often appear in characteristic weight ranges depending on how they are spun and woven.
Hemp fibres, for example, are naturally strong and relatively long. This allows them to be woven into fabrics that maintain stability even at lighter weights — useful for curtains where a fabric still needs to hold its form in pleats and folds. At heavier weights, hemp can produce dense, durable cloths suited to upholstery and hard-working interior applications.
Linen and cotton also behave differently across weight ranges. Lightweight linen can feel crisp and airy, while heavier linens often become beautifully substantial and textural. Cotton spans a wide range too: from light poplins and voiles, through midweight twills and drills, to heavy cotton canvas. Wool and wool blends can add bulk and warmth at mid-to-heavy weights, often with a softer “loft” rather than the flatter, firmer structure of many plant-fibre canvases.
Modern spinning and finishing techniques allow hemp fabrics to be produced across a wide range of weights, from lighter curtain fabrics to dense upholstery textiles.
Explore our full range in the Hemp Fabrics collection.
Choosing the right fabric weight
When selecting fabric for interiors, the appropriate weight depends on the intended use — and on what you want the textile to do in the room.
For curtains, lighter weights (often 100–250 gsm, depending on weave) tend to give a softer, airier effect and allow light to filter gently. Midweight curtain fabrics (often around 200–350 gsm) provide more presence, deeper folds, and greater privacy, while still draping well. Very heavy fabrics can work for dramatic, structured curtains, but they may feel more architectural and less fluid — and can require stronger heading tape and hardware.
For upholstery, durability and stability become more important. In general, frequently used furniture benefits from heavier, denser cloths (often 350 gsm and above), particularly where the weave is tight and the surface can withstand abrasion. Decorative or occasional upholstery can sit in midweights, especially when the piece won’t see constant wear. Cushions and soft furnishings can sit across midweights depending on the look you want: crisp and structured, or softer and more relaxed.
If you are comparing options, it can help to think in simple practical terms:
- want a light-filtering, airy curtain → lighter weight + good drape
- want curtains with more body and privacy → midweight + stable weave
- want furniture fabric that holds shape → heavier weight + dense construction
- want cushions with structure → mid-to-heavy depending on firmness desired
Understanding fabric weight can help narrow down suitable options, but it is best considered alongside other qualities such as weave, texture and drape. Together, these characteristics determine how a fabric will behave once it becomes part of an interior space.