Work out warp and weft count instantly with clear inputs, formula shown and shareable results.
Fabric weight is built from thread density and yarn count in each direction, with a crimp allowance — around 6% for warp and 2% for weft in a plain weave. Cover factor, the sum of density divided by the square root of count in each direction, indicates how tightly the cloth is set and whether it can be woven at all.
GSM from construction
Warp GSM = EPI x 25.4 / Ne x 0.5905 x crimp factor; total GSM = warp + weft contributions
Cover factor
Cover factor = EPI / sqrt(warp Ne) + PPI / sqrt(weft Ne)
Up to about 28 for a plain weave; beyond that the shed cannot be cleared and the cloth jams. Twills and satins allow higher cover factors because they have fewer interlacings.
Crimp allowances vary with weave and tension, finishing adds or removes weight, and yarn count tolerance is typically 2-3%. Agreement within 5% is normal.