Fabric Air Permeability Calculator
Reviewed by Hamza Gujjar, Algorithm Architect & Software Developer
Last updated: July 28, 2026Fabric Air Permeability Calculator
Testing fabric breathability? This calculator converts raw airflow test data into a standard air permeability figure.
Permeability (mm/sec) = (Airflow Rate(L/sec) x 1,000,000) / Test Area(cm┬▓) / 100
Example
50 L/min airflow rate through a standard 20 cm┬▓ test area:
Airflow Rate = 0.833 L/sec → ~417 mm/sec air permeability
Why This Matters for Fabric Selection
Air permeability measures how easily air passes through a fabric - high permeability suits breathable summer clothing and activewear designed to release body heat and moisture, while low permeability is desirable for windbreakers, technical outerwear, and any fabric requiring meaningful wind or water resistance.
Comparing Fabrics Fairly
Since permeability is measured against a standardized test area, comparing results across different fabric samples tested under this same standard method gives a fair, apples-to-apples comparison of relative breathability between materials.