Kilopascals to Newtons per Square Millimetre (kPa to N/mm2)

Formula

N/mm² = kPa ÷ 1000

Derivation from SI units:

• 1 kPa = 10³ Pa
• 1 N/mm² = 1 N ÷ 10⁻⁶ m² = 10⁶ Pa = 1 MPa
• 1 kPa = 1000 Pa ÷ 1000000 Pa per N/mm² = 0.001 N/mm²

Both units are defined exactly, so the factor is exact. Kilopascal definition: kilopascal; Newton per Square Millimetre definition: newton per square millimetre.

Worked examples

1. A reading of 20 kPa converts to 0.02 N/mm².
   20 kPa × 0.001 = 0.02 N/mm²
2. A value of 300 kPa is 0.3 N/mm².
   300 kPa × 0.001 = 0.3 N/mm²

Where it's used

Kilopascals are used for tyre pressure outside the United States (about 200–250 kPa for cars), 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.

Kilopascal 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 7, SI prefixes.
• 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.