Convert Kilograms-force per Square Millimetre to N/mm²

Formula

N/mm² = kgf/mm² × 9.80665

Derivation from SI units:

• 1 kgf/mm² = 9.80665 N ÷ 1 mm² = 9.80665 MPa (exact)
• 1 N/mm² = 1 N ÷ 10⁻⁶ m² = 10⁶ Pa = 1 MPa
• 1 kgf/mm² = 9806650 Pa ÷ 1000000 Pa per N/mm² = 9.80665 N/mm²

Both units are defined exactly, so the factor is exact. Kilogram-force per Square Millimetre definition: kilogram-force per square millimetre; Newton per Square Millimetre definition: newton per square millimetre.

Worked examples

1. A reading of 24 kgf/mm² converts to 235.3596 N/mm².
   24 kgf/mm² × 9.80665 = 235.3596 N/mm²
2. A value of 50 kgf/mm² is 490.3325 N/mm².
   50 kgf/mm² × 9.80665 = 490.3325 N/mm²

Where it's used

Kilograms-force per Square Millimetre are used for tensile strength in older JIS and GB steel standards, while newtons per square millimetre appear in steel yield and tensile strength (S355: 355 N/mm²). Both measure pressure, stress and differential pressure (force per unit area), so the conversion is a fixed factor.

Kilogram-force per Square Millimetre 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, "kilogram-force per square millimeter".
• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 4, coherent derived units with special names.

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