Fabric length to weight converter
Convert between fabric length and weight when you know the usable width and GSM - for checking roll weights, ordering knit fabric by the kilo, or estimating metres in a delivery.
How this is calculated
From the definition of GSM: weight (kg) = length (m) × width (m) × GSM ÷ 1000, and so length (m) = weight (kg) × 1000 ÷ (width (m) × GSM). Width in inches is converted with 1 in = 2.54 cm; yards with 1 yd = 0.9144 m.
Worked example. 100 m of 150 cm fabric at 180 GSM weighs 100 × 1.5 × 180 ÷ 1000 = 27 kg. One running metre weighs 1.5 × 180 = 270 g, so 27 kg is 100 m.
Questions
- Which width should I use?
- The width you will actually use, measured the same way the GSM was measured. For woven fabric that is usually the cuttable width inside the selvedges; for tubular knits, use the open width (twice the tube width).
- Why does my roll weigh more than this?
- Roll weight includes the tube and packing, and the fabric may carry more moisture or finish than the GSM sample. Compare net weight, and check GSM on the same roll.
Sources & verification
The relation follows directly from mass per unit area as defined in ASTM D3776 and ISO 3801. The worked example is recomputed in the automated tests.