Convert Newtons per Square Millimetre to kgf/mm²

Formula

kgf/mm² = N/mm² × 0.1019716212978

or kgf/mm² = N/mm² ÷ 9.80665

Derivation from SI units:

• 1 N/mm² = 1 N ÷ 10⁻⁶ m² = 10⁶ Pa = 1 MPa
• 1 kgf/mm² = 9.80665 N ÷ 1 mm² = 9.80665 MPa (exact)
• 1 N/mm² = 1000000 Pa ÷ 9806650 Pa per kgf/mm² = 0.1019716212978 kgf/mm²

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

Worked examples

1. A reading of 30 N/mm² converts to 3.059148639 kgf/mm².
   30 N/mm² × 0.1019716213 = 3.059148639 kgf/mm²
2. A value of 275 N/mm² is 28.04219586 kgf/mm².
   275 N/mm² × 0.1019716213 = 28.04219586 kgf/mm²

Where it's used

Newtons per Square Millimetre are used for steel yield and tensile strength (S355: 355 N/mm²), 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.

Newton per Square Millimetre to other pressure units

Frequently asked questions

Sources

• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 4, coherent derived units with special names.
• 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.