Convert Inches of Mercury to kgf/mm²

Formula

kgf/mm² = inHg × 0.00034531554

or kgf/mm² = inHg ÷ 2895.902107389

Derivation from SI units:

• 1 inHg = 13 595.1 kg/m³ × 9.80665 m/s² × 0.0254 m = 3386.388640341 Pa
• 1 kgf/mm² = 9.80665 N ÷ 1 mm² = 9.80665 MPa (exact)
• 1 inHg = 3386.388640341 Pa ÷ 9806650 Pa per kgf/mm² = 0.00034531554 kgf/mm²

Both units are defined exactly, so the factor is exact. Inch of Mercury definition: inch of mercury; Kilogram-force per Square Millimetre definition: kilogram-force per square millimetre.

Worked examples

1. A reading of 15 inHg converts to 0.0051797331 kgf/mm².
   15 inHg × 0.00034531554 = 0.0051797331 kgf/mm²
2. A value of 29 inHg is 0.01001415066 kgf/mm².
   29 inHg × 0.00034531554 = 0.01001415066 kgf/mm²

Where it's used

Inches of Mercury are used for aircraft altimeter settings (standard 29.92 inHg), while kilograms-force per square millimetre appear in tensile strength in older JIS and GB steel standards. Both measure pressure, stress and differential pressure (force per unit area), so the conversion is a fixed factor.

Inch of Mercury 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 mercury, conventional (inHg)".
• 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, "kilogram-force per square millimeter".

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