Warp And Weft Count Calculator

Work out warp and weft count instantly with clear inputs, formula shown and shareable results.

About Warp And Weft Count Calculator

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.

Formulas

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)

Worked example

With the default values below, Warp And Weft Count Calculator returns Calculated Fabric GSM of 49.98. Change any input above and every figure here is recalculated in your browser.

Inputs used

Ends Per Inch (warp density)minimum 0.01: 68
Picks Per Inch (weft density)minimum 0.01: 60
Warp Yarn Countminimum 0.01 Ne: 40 Ne
Weft Yarn Countminimum 0.01 Ne: 40 Ne

Results

Calculated Fabric GSM: 49.98
Warp Contribution To GSM: 27.03
Weft Contribution To GSM: 22.95
Cover Factor: 20.239

Step by step

1Values used
2GSM from construction
3Cover factor
4Calculated Fabric GSM= 49.98
5Warp Contribution To GSM= 27.03
6Weft Contribution To GSM= 22.95
7Cover Factor= 20.239

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What cover factor is weavable?

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.

Why do calculated and measured GSM differ?

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.