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Calcimator

Loom Width Calculator

Minimum weaving width from finished width and shrinkage.

Inputs

%
%

Results

Required width on loom (in)

21.6

Minimum loom size (in)

22

Total warp ends259
Draw-in loss (inches)1.6
Shrinkage loss (inches)0.9
How to Use This Calculator
  1. Enter the desired finished width of the fabric in inches after washing.
  2. Set the draw-in percentage (width lost on the loom from weft tension) — typically 5–10%.
  3. Set the shrinkage percentage (width lost during wet-finishing) — cotton ~5%, wool ~10%.
  4. Enter your warp sett in ends per inch (EPI).
  5. Set the selvedge allowance in inches per side for floating selvedge or doubled selvedge ends.
  6. Read the required width on the loom and the minimum standard loom size that can accommodate it.

How the result changes with Finished width (inches)

Finished width (inches)Required width on loom (in)Minimum loom size (in)
6.98.910
2226.227
3945.648
5462.860

What each input means

Finished width (inches)
Desired finished width of the fabric after washing.
Draw-in %
Width loss on the loom from weft tension. Typically 5-10%.
Shrinkage %
Width loss during wet-finishing. Cotton ~5%, wool ~10%.
Ends per inch (EPI)
Warp sett — affects total number of ends to thread.
Selvedge allowance per side (in)
Extra width per side for floating selvedge or doubled ends.

What each result means

Required width on loom (in)
Total width to warp including all allowances.
Minimum loom size (in)
Smallest standard loom that fits this warp.
Total warp ends
Number of warp threads to thread at this width and sett.
Draw-in loss (inches)
Width lost to draw-in on the loom.
Shrinkage loss (inches)
Width lost during wet-finishing.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Finished width (inches) = 18, Draw-in % = 8, Shrinkage % = 5, Ends per inch (EPI) = 12 = 5 input(s) provided
  2. Calculate Required width on loom
    Required width on loom = widthOnLoom + selvedgeExtra * 2
    21.6 = 21.6
  3. Calculate Minimum loom size
    Minimum loom size = standardLooms[standardLooms.length - 1]
    22 = 22
  4. Calculate Total warp ends
    Total warp ends = round(totalWidthNeeded * epi)
    259 = 259
  5. Calculate Draw-in loss
    Draw-in loss = widthOnLoom - widthBeforeShrinkage
    1.6 = 1.6

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