Convert Inches of Water to Baryes

Formula

Ba = inH₂O × 2490.8891

Derivation from SI units:

• 1 inH₂O = 1000 kg/m³ × 9.80665 m/s² × 0.0254 m = 249.08891 Pa
• 1 Ba = 1 dyn/cm² = 10⁻⁵ N ÷ 10⁻⁴ m² = 0.1 Pa
• 1 inH₂O = 249.08891 Pa ÷ 0.1 Pa per Ba = 2490.8891 Ba

Both units are defined exactly, so the factor is exact. Inch of Water definition: inch of water; Barye definition: barye.

Worked examples

1. A reading of 0.3 inH₂O converts to 747.26673 Ba.
   0.3 inH₂O × 2490.8891 = 747.26673 Ba
2. A value of 3 inH₂O is 7472.6673 Ba.
   3 inH₂O × 2490.8891 = 7472.6673 Ba

Where it's used

Inches of Water are used for HVAC total external static pressure (residential ≈ 0.5 inH₂O), while baryes appear in older physics and acoustics literature. Both measure pressure, stress and differential pressure (force per unit area), so the conversion is a fixed factor.

Inch of Water to other pressure units

Frequently asked questions

Sources

• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "inch of water, conventional (inH2O)".
• Guide for the Use of the International System of Units (SI), NIST Special Publication 811, 2008 Edition, National Institute of Standards and Technology , Appendix B.8, "dyne per square centimeter (dyn/cm²)".

Last reviewed: 2026-10-15. Factors are stored exactly and computed with 50-digit decimal arithmetic. See how we verify conversion factors.