Convert psi to Inches of Water (60 °F)

Formula

inH₂O (60 °F) = psi × 27.70759240142

Derivation from SI units:

• 1 psi = 1 lbf/in² = (0.45359237 kg × 9.80665 m/s²) ÷ (0.0254 m)² = 6894.757293168 Pa
• 1 inH₂O (60 °F) ≈ 999.0 kg/m³ × 9.80665 m/s² × 0.0254 m ≈ 248.84 Pa
• 1 psi = 6894.757293168 Pa ÷ 248.84 Pa per inH₂O (60 °F) = 27.70759240142 inH₂O (60 °F)

One unit is a measured value, so the factor is approximate. psi definition: psi; Inch of Water (60 °F) definition: inch of water (60 °F).

Worked examples

1. A reading of 14.7 psi converts to 407.3016083 inH₂O (60 °F).
   14.7 psi × 27.7075924 = 407.3016083 inH₂O (60 °F)
2. A value of 60 psi is 1662.455544 inH₂O (60 °F).
   60 psi × 27.7075924 = 1662.455544 inH₂O (60 °F)

Where it's used

psi are used for tyre pressure in the United States (about 30–35 psi for cars), while inches of water (60 °F) appear in older US gas-industry and flow-meter references. Both measure pressure, stress and differential pressure (force per unit area), so the conversion is a fixed factor.

psi 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, "pound-force per square inch (psi)".
• 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 (60 °F)".

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