Skip to content

Weaving & Fiber Calculator

Warp Calculator. Calculate warp yarn requirements for loom weaving projects. Estimate total warp threads, yardage, and sett from project width and EPI.

Use this result well

Inputs that matter
Project Width, Sett (EPI), Project Length, Loom Waste, and 1 more
Output to expect
Warp Yarn Calculator
  • Check the units and required inputs before comparing results.
  • Keep the assumptions with a copied result so you can reproduce the calculation later.
Was this tool helpful?

Related Tools

Tools you might need next

Yarn Yardage Calculator

Calculate total yarn yardage for weaving projects including warp and weft. Estimate cones needed from project dimensions and yarn weight.

Recommended next stepWeaving
Warp Length Calculator

Calculate total warp length including loom waste, take-up, and shrinkage for weaving projects. Plan yarn requirements accurately.

Recommended next stepWeaving
Sett Calculator

Calculate optimal weaving sett (EPI and PPI) from yarn wraps per inch and weave structure. Balanced, warp-faced, and weft-faced sett guide.

Recommended next stepWeaving

Reference & details

How it works

Total Warp Ends

Multiply weaving width by sett (EPI). Add 4–8 selvedge ends total (2–4 per side) for stable edges.

Ends = Project width (in) × EPI + Selvedge ends

Warp Length per End

Add loom waste for threading, tying on, and fringe. Front and back loom waste typically 18 inches each.

Length per end = Warp length + Loom waste (27–36 in)

Total Warp Yardage

Multiply ends by length per end, convert to yards. Add 10% for tension variation and mistakes during warping.

Yards = (Ends × Length per end in inches) ÷ 36

Updated: July 2026

Example Scenarios

168 ends (160 + 8 selvedge) × 3 yard warp plus 30 inches waste = 504 end-yards ≈ 14 yards total warp yarn.

364 ends × 4 yard warp length = 1456 end-yards ≈ 40 yards of 8/2 cotton warp yarn.

900 ends at 12 EPI × 5 yards plus waste = 4500+ end-yards. Order 130 yards accounting for 10% buffer.

FAQ

Ends Per Inch — the number of warp threads per inch of width. EPI depends on yarn size and weave structure. Check sett charts or wrap yarn around ruler for wraps per inch (WPI) to determine EPI.

Typically 18–27 inches total: 9–14 inches front (between warp beam and fell) plus 9–14 inches back. Add fringe length separately if included in warp.

2–4 doubled threads per selvedge edge (4–8 total ends). Plain weave selvedges need fewer; slippery yarn needs more for stable edges.

Use whichever matches your yarn supplier. Convert: 1 yard = 0.914 meters. Most weaving yarn is sold by cone yardage in yards (US) or meters (UK/EU).

Sley multiple ends per dent or skip dents to achieve target EPI. A 12-dent reed with 2 ends per dent = 24 EPI. Adjust project width or reed size accordingly.

About Warp Calculator

Warp planning determines yarn quantity, loom threading, and project width. Enter project width, EPI (ends per inch), warp length, and number of ends to calculate total warp threads and yarn yardage needed including loom waste.