Yarn Twist Converter
Yarn Twist Converter: convert between 4 yarn twist units, for example 1 TPI = 39.37007874 TPM.
| Unit | Value |
|---|---|
| turn per inch to turn per metre | 39.37007874 TPM |
| turn per inch (TPI) | 1 TPI |
| turn per inch to turn per centimetre | 0.3937007874 TPcm |
| turn per inch to turn per foot | 12 TPF |
Convert yarn twist between turns per inch (TPI), turns per metre (TPM), turns per centimetre and turns per foot. All factors are exact: 1 TPI = 39.37007874 TPM because an inch is exactly 0.0254 m.
Twist and twist multiplier
Twist alone does not compare yarns of different fineness. The twist multiplier does: TM = TPI ÷ √Ne on the cotton system and αm = TPM ÷ √Nm on the metric system, with TM ≈ αm ÷ 30.25.
Yarn Twist unit definitions
- turn per metre (TPM)
- Turns per metre (TPM) counts the complete twists a yarn makes about its axis in one metre. Ring-spun cotton yarns run about 500–1100 TPM, finer yarns higher.
- turn per inch (TPI)
- Turns per inch (TPI) is the twist count of the cotton system. With English count Ne, the twist multiplier is TM = TPI ÷ √Ne; hosiery yarns use about 3.2–3.6 and warp yarns 4–4.5.
- turn per centimetre (TPcm)
- Turns per centimetre is 100 TPM. It is handy for filament and ply twist, where values are small, and on some twist testers.
- turn per foot (TPF)
- Turns per foot is used for cords, ropes and cables, where twist is low: 12 turns per foot equals 1 TPI.
Popular yarn twist conversions
- turn per metre to turn per inch
- turn per inch to turn per metre
- turn per inch to turn per centimetre
- turn per centimetre to turn per inch
Show all 12 yarn twist conversions
From turns per metre
From turns per inch
From turns per centimetre
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- Printable yarn twist conversion chart – print, PDF or PNG
- yarn twist and twist multiplier calculator
- yarn count converter (tex, Ne, Nm, denier)
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Sources
- ISO 1144, Textiles — Universal system for designating linear density (Tex System), International Organization for Standardization.
- Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology.
- The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures.
Last reviewed: .