Rigid Heddle Project Planner Calculator

A rigid heddle loom simplifies the usual warp planning because one number does double duty: the heddle's dent count (slots plus holes per inch) fixes both your ends-per-inch sett and, since this planner assumes a balanced plain weave, your picks-per-inch as well — so entering the correct heddle size (commonly 5, 8, 10, or 12 dent) drives most of the downstream math. The calculator applies a fixed 7% draw-in to find the width you actually need to warp, checks that width against your loom's maximum weaving width to flag whether the project fits at all, and multiplies warp width by sett to get total ends. Warp length works backward from your finished length through take-up (shortening from the warp bending over and under the weft as it interlaces) and shrinkage (further contraction during wet-finishing), then adds a flat 30 inches of loom waste — rigid heddle setups typically lose more warp to tie-on and loom waste than multi-shaft floor looms, so this figure runs higher than you'd budget on a jack or countermarch loom.

Weft yardage comes from total picks (woven length times PPI) times the on-loom width, inflated by 10% to cover how weft doesn't travel perfectly straight but bows slightly as it interlaces with the warp. Both warp and weft yardages are then divided by your yarn's yards-per-ball to tell you how many balls or skeins to buy, either combined (if using one yarn for both) or separately. Because the 7% draw-in and 30-inch waste figures are fixed assumptions rather than inputs, a project with an unusually stiff or slippery yarn, or a loom with more or less waste than typical, may need you to pad the suggested yardage further — buy a bit extra rather than running short partway through weaving.