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Weaving Loom Sett Calculator

Estimate sett, warp ends, and a practical reed starting point from yarn and weave structure

Recommended Sett

13 epi

Warp Ends

312

Range

12-14

Recommended Sett

13

ends per inch

Working Range

12 to 14

Warp Ends

312

Suggested Reed

6-dent

Ends Per Dent

2.2

Structure vs Sett Factor

StructureWPI FactorCloth Feel
Plain Weave50%Firm, balanced
Twill42%Soft drape
Basket Weave45%Textured
Lace33%Open, airy
Rug25%Open warp

Tips

Yarn substitution: If substituting yarn, match WPI, not weight class. A loose bulky and a tight worsted can have the same WPI but different results.
Reed selection: Aim for 1.5–2.5 ends per dent. Outside this range, threads bunch or spread unevenly.
Always sample: These numbers are starting points. Weave a 4–6 inch sample, wash it, and measure the finished cloth before committing to a full warp.

Example Calculations

124" Width, 24 WPI Cotton, Plain Weave, Balanced

Inputs

Weaving Width24 in
Wraps Per Inch24
StructurePlain Weave
FiberCotton
BalanceBalanced

Result

Recommended Sett13 epi
Working Range12–14 epi
Total Warp Ends312
Suggested Reed6-dent
Ends Per Dent2.2

Sett = 24 × 0.50 (plain) × 1.05 (cotton) × 1.0 (balanced) = 12.6, rounded to 13. Warp ends = 24 × 13 = 312. Best reed = 6-dent at 2.2 ends/dent.

215" Width, 30 WPI Wool, Twill, Warp-Faced

Inputs

Weaving Width15 in
Wraps Per Inch30
StructureTwill
FiberWool
BalanceWarp-Faced

Result

Recommended Sett14 epi
Working Range13–15 epi
Total Warp Ends210
Suggested Reed8-dent
Ends Per Dent1.8

Sett = 30 × 0.42 (twill) × 0.95 (wool) × 1.15 (warp-faced) = 13.76, rounded to 14. Warp ends = 15 × 14 = 210. Best reed = 8-dent at 1.75 ends/dent.

Frequently Asked Questions

Q

What is sett in weaving?

Sett is the number of warp ends per inch (EPI) in the reed. It determines how open, balanced, or firm the cloth becomes. A 24 WPI cotton yarn at plain weave gives about 13 EPI sett.

  • Low sett: open, drapey fabric – good for scarves and shawls
  • Balanced sett: equal coverage of warp and weft – standard tableware and towels
  • High sett: firm, dense fabric – good for upholstery and rugs
  • Sett that is too tight prevents the weft from interlacing properly
  • Sett that is too loose makes sleazy, unstable cloth
Yarn WPIPlain Weave SettTwill Sett
12 (bulky)6–7 epi5–6 epi
18 (worsted)9–10 epi8–9 epi
24 (sport)12–14 epi10–12 epi
30 (fingering)15–17 epi13–15 epi
Q

Why do different weave structures use different sett?

Plain weave interlaces on every pick, creating the most friction between threads. This means it needs a tighter sett. Twill, lace, and rug structures interlace less frequently and use progressively more open setts.

  • Plain weave: 50% of WPI – most interlacing, tightest sett
  • Basket weave: 45% of WPI – paired threads, slightly more open
  • Twill: 42% of WPI – less interlacing, floats allow closer packing
  • Lace: 33% of WPI – deliberately open for light, airy cloth
  • Rug: 25% of WPI – very open warp to pack thick weft tightly
StructureWPI FactorCharacteristic
Plain50%Firm, balanced
Twill42%Soft drape, diagonal pattern
Basket45%Textured, paired threads
Lace33%Open, airy, light
Rug25%Open warp, packed weft
Q

How does fiber type affect sett?

Different fibers compress differently. Cotton and linen are less compressible than wool, so they need slightly higher sett (5–12% more EPI) for equivalent coverage.

  • Wool: 95% baseline – compresses easily, fills gaps between threads
  • Cotton: 105% – round, smooth fiber, needs closer spacing
  • Linen: 112% – stiff, flat fiber, needs even closer spacing
  • Silk: 108% – smooth and slippery, needs tighter sett to prevent shifting
Q

What is cloth balance and why does it matter?

Cloth balance describes the relative prominence of warp vs weft in the finished fabric. Balanced cloth shows equal warp and weft. Warp-faced cloth needs a tighter sett to cover the weft; weft-faced needs a looser sett.

  • Balanced: 1.0× – equal warp and weft visibility
  • Warp-faced: 1.15× – warp covers weft, needs more ends per inch
  • Weft-faced: 0.85× – weft covers warp, fewer ends needed
  • Rep weave is an extreme warp-faced structure needing very high sett
Q

How do I choose the right reed?

The calculator suggests a reed that gives close to 2 ends per dent, which is the easiest sleying pattern. For example, 13 EPI works best in a 6-dent reed (2.2 ends per dent).

  • Common reed sizes: 5, 6, 8, 10, 12, 15 dents per inch
  • Target 1.5–2.5 ends per dent for easy, consistent sleying
  • 1 end/dent: fastest sleying but limited to reeds matching your EPI
  • 2 ends/dent: most common, works with a wide range of reeds
  • 3 ends/dent: acceptable but can crowd threads in fine work

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Last Updated: Mar 11, 2026

This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.

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