Fabric weight is usually expressed in GSM, meaning grams per square metre. A higher GSM means the fabric has more mass per square metre, but it does not automatically mean the fabric is more durable, warmer or suitable for upholstery. Construction, fibre, weave, finish and intended use all matter.
For curtains, weight influences drape, fullness and the load placed on the pole or track. For upholstery, GSM can help describe the handle and substance of a fabric, but abrasion performance should be checked separately through the Martindale result and the supplier's intended-use guidance.
Reviewed and updated by The Millshop Online fabric team: August 2026.
What does GSM mean for fabric?
GSM stands for grams per square metre. It describes how much one square metre of fabric weighs. The measurement is useful because it allows fabrics of different widths to be compared on the same area basis.
For woven fabrics, mass per unit area is covered by testing methods such as ISO 3801. A GSM figure describes mass, not the complete performance of the material.
Indicative fabric weight ranges
There is no universal GSM boundary for curtain or upholstery fabric. A dense lightweight synthetic and an open heavier natural weave can behave very differently. The ranges below are a practical starting point only.
| Approximate weight | General description | Possible interiors uses |
|---|---|---|
| Below 150 GSM | Lightweight | Voiles, light curtains, decorative linings and some craft projects |
| 150-250 GSM | Medium weight | Many curtains, Roman blinds, cushions and suitable multi-use fabrics |
| 250-400 GSM | Heavy furnishing weight | Fuller curtains, structured blinds and upholstery where the product is approved |
| Above 400 GSM | Very heavy | Dense weaves, some velvets and specialist upholstery or curtain applications |
Do not select a fabric from the GSM band alone. Check the individual product description for curtains, blinds, cushions, domestic upholstery or contract upholstery.
Is fabric gauge the same as GSM?
No. GSM is mass per unit area. Gauge is more commonly used for knitted construction and describes the fineness or density of stitches or needles over a set distance. It does not provide the weight of a fabric and should not be used as a substitute for GSM.
Thread count, yarn thickness and weave density are also separate measurements. They can influence handle and performance, but none of them alone establishes whether a fabric is suitable for a sofa, curtain or blind.
Does heavier fabric mean more durable fabric?
Not necessarily. A heavy, open or delicate weave may snag or distort more easily than a lighter but tightly constructed upholstery fabric. A high GSM also does not prove abrasion resistance.
For seating, compare the Martindale rub count and intended use as well as weight. Our Martindale rub test guide explains the commonly used domestic and contract ranges.
GSM versus Martindale rub count
| Measurement | What it tells you | What it does not prove |
|---|---|---|
| GSM | Mass of fabric per square metre | Abrasion resistance, fire performance or cleanability |
| Martindale rub count | Resistance to repeated abrasion under a laboratory method | Weight, drape, stain resistance or fire performance |
| Intended use | Applications approved by the supplier | That the fabric will suit every construction method or room |
The most useful buying decision combines all three, supported by a physical sample.
What fabric weight is best for curtains?
The best weight depends on the desired finish:
- Lightweight curtain fabric can create an airy, relaxed look but may require lining for privacy, body and protection.
- Medium-weight curtain fabric is a versatile choice for many living rooms, bedrooms and Roman blinds.
- Heavy curtain fabric creates a fuller, more substantial appearance, but the pole, track and heading must support the finished weight.
Weight alone does not determine warmth or blackout performance. Fibre, weave, window fit and the chosen lining make a substantial difference. Read our curtain fabric buying guide and lining and interlining guide before deciding.
Browse curtain fabric by the metre and check the product width, weight, pattern repeat and recommended uses together.
What fabric weight is best for Roman blinds?
Roman blinds generally need enough body to form neat folds without becoming excessively bulky. Many medium-weight curtain and multi-use fabrics work well, but stability is more important than a particular GSM figure.
Very loose, stretchy or heavy fabrics can be difficult to control. Lining, pattern placement, the size of the blind and the capacity of the chosen system should all be considered.
What fabric weight is best for upholstery?
Upholstery fabric needs stable construction and suitable abrasion performance. A medium or heavy furnishing fabric may feel substantial, but it should still be specifically approved for the intended furniture.
For a family sofa or frequently used dining chairs, start with upholstery fabric that states its Martindale result and intended use. The upholstery fabric buying guide compares wear, weave, care and pattern in more detail.
For contract upholstery, weight and rub count still do not replace the fire and performance specification required by the project.
What fabric weight is best for cushions?
Decorative cushions allow more flexibility than seating. A lighter curtain fabric can work well for a cushion that is mainly decorative, while a cushion used daily on a family sofa may benefit from a more substantial, tightly constructed fabric.
Also check seam stability, cleaning guidance and whether piping or a zip will add stress to the fabric. When coordinating cushions and curtains, the same design may be available on different basecloths, so confirm which weight you are ordering.
How to compare fabric weights online
- Check the GSM or stated fabric weight where available.
- Confirm the intended use: curtain, blind, cushion, domestic upholstery or contract upholstery.
- Check fabric width and pattern repeat.
- For upholstery, compare the Martindale result separately.
- For curtains, consider lining, fullness and the strength of the track or pole.
- Order a sample to assess thickness, flexibility, texture and drape.
Frequently asked questions
Is 200 GSM suitable for curtains?
It can be. A fabric around 200 GSM often falls within a versatile medium-weight range, but the weave, opacity, drape and intended use should also be checked.
Is 300 GSM suitable for upholstery?
The weight may feel substantial, but GSM does not prove upholstery durability. Confirm that the product is upholstery grade and check its Martindale result.
Does a higher GSM make curtains warmer?
Not automatically. A heavier fabric can add substance, but construction, lining, window fit and air gaps all influence thermal performance.
Can the same design have different fabric weights?
Yes. A print may be offered on a lighter curtain basecloth and a heavier upholstery basecloth. Check the exact version and intended use before ordering.
Use GSM to understand the weight and handle of a fabric, then combine it with construction, intended use, care information and relevant performance tests. That gives a much more reliable choice than treating the heaviest fabric as automatically the best.
