Textile Engineering Calculators and Formulas

Textile Engineering Formulas and Calculators

• Air Permeability Calculator

  R = q ÷ A

  R air permeability, q air flow through the sample, A test area

  Example: 12 L/min ÷ 20 cm² = 100 mm/s.

  Open the air permeability calculator →

• Bubble Point Pore Size Calculator

  d = 4 k γ cos θ ÷ ΔP

  d pore size, k pore shape factor, γ surface tension, θ contact angle, ΔP bubble-point pressure

  Example: 30 psi with isopropyl alcohol gives 0.42 µm (k = 1).

  Open the bubble point pore size calculator →

• Face Velocity Calculator

  v = Q ÷ A

  v face velocity, Q airflow, A face area

  Example: 2000 CFM ÷ 4 ft² = 500 ft/min.

  Open the face velocity calculator →

Unit Converters for Textile Engineering

• Yarn Count Converter – tex, dtex, denier, Ne, Nm, worsted
• Face Velocity & Air Permeability Converter – CFM/ft², L/(m²·s), mm/s, cm/s, ft/min
• Weight and Mass Converter – kg, g, mg, lb, oz, st, t, ton, oz t, ct
• Length Converter – m, km, cm, mm, µm, ft, in, mi, yd, nmi
• Area Converter – m², cm², mm², ft², in², test areas
• Pressure Converter – Pa, kPa, psi, bar, inH₂O, mmHg, torr, atm

Common Textile Engineering Conversions

• denier to tex
• tex to denier
• cubic foot per square foot per minute to liter per square meter per second
• liter per square meter per second to cubic foot per square foot per minute
• kilogram to pound
• pound to kilogram
• centimeter to inch
• inch to centimeter
• square meter to square foot
• square foot to square meter
• pascal to psi
• psi to pascal

Using these textile engineering calculators

Textile work mixes metric and traditional units more than almost any other field. Yarn fineness can be given as tex or decitex (mass per length) or as cotton count Ne or metric count Nm (length per mass), and the two families are reciprocal: a higher tex is a coarser yarn, a higher Ne is a finer one. The yarn count converter handles both directions with the exact hank and pound constants.

Fabric air permeability is measured by drawing air through a fixed test area at a set pressure drop, typically 100 Pa for apparel (ISO 9237) or 125 Pa (ASTM D737). The air permeability calculator turns the tester flow and head size into mm/s, L/m²/s or cfm/ft², so results from different machines can be compared.

For nonwovens and filter media, the bubble-point method estimates the largest pore from the pressure at which a wetting liquid is first pushed out. The surface tension of the liquid and the shape factor of the pores both change the answer, so the calculator lets you set them explicitly.