Weaving Warp Yarn Calculator

Separate width planning from length planning

Width in the reed multiplied by sett determines the base number of warp ends. This is not a prediction of finished width: you need a sample to account for draw-in and sideways finishing shrinkage. Additional selvedge ends are added after rounding the base count upward. Adjust that total yourself if your threading repeat requires a particular multiple.

Yarn formulas and denominator convention

Ends E = ceil(reed width × ends per inch) + additional ends. For finished length L, take-up loss fraction t, and finishing loss fraction s, woven-section yarn per piece = L / [(1 - t) × (1 - s)]. Per-end warp length P = pieces × [woven-section yarn + 2 × raw fringe allowance] + loom waste. Total yards = E × P / 36. Skeins = ceil(total yards / usable yards per skein). Purchase cost = skeins × price.

Some weaving plans instead define take-up as a percentage added to woven length. Do not copy that percentage here unchanged. For example, 10% added allowance corresponds to a loss fraction of 10 / 110 = 9.0909%. This page explicitly uses loss fractions for sequential stages. Loom waste is counted once for one setup; separate warps each need their own waste allowance.

Worked example: two 60-inch pieces

At 10 inches in the reed and 20 ends/inch, plus four selvedge ends, there are 204 ends. With 10% take-up and 5% finishing loss, each 60-inch woven section needs 70.1754 inches of straight warp yarn. Add 4 inches at both ends of each piece and 24 inches loom waste once: per-end length is 180.3509 inches, or 5.0097 yd. Total warp is 1,021.9883 yd; buy 3 skeins of 400 yd, leaving 178.0117 yd and costing $54 at $18 each.

Interpretation and limits before winding

The leftover output is purchased yardage minus the modeled warp, not a guarantee that every remnant is usable. Keep dye lots consistent and budget sampling yarn separately. This calculator excludes weft, hems beyond your entered allowances, repair ends, knots within skeins, and pattern-specific threading constraints. It assumes identical pieces, equal-length ends, and uniform losses. Display values use at most four decimals; round winding length upward rather than cutting too short.

The inch-to-yard ratio and the inventory rounding are exact arithmetic. There are no empirical yarn presets or recommended shrinkage rates in this model; enter measured values from your own weave and finishing process. Field bounds limit the planner to positive dimensions, whole piece/extra-end counts, and losses no greater than 50% per stage.

Related tools

• Fabric shrinkage yardage plans purchased cloth after washing, rather than loom ends or warp yarn.
• Inches to centimeters helps translate a metric weaving plan before using these inch-based inputs.

Last updated: 2026-10-09. Verify length-loss conventions with your weaving notes.