Millibars to Newtons per Square Millimetre (mbar to N/mm2)

Formula

N/mm² = mbar ÷ 10000

Derivation from SI units:

• 1 mbar = 10⁻³ bar = 100 Pa = 1 hPa
• 1 N/mm² = 1 N ÷ 10⁻⁶ m² = 10⁶ Pa = 1 MPa
• 1 mbar = 100 Pa ÷ 1000000 Pa per N/mm² = 0.0001 N/mm²

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

Worked examples

1. A reading of 20 mbar converts to 0.002 N/mm².
   20 mbar × 0.0001 = 0.002 N/mm²
2. A value of 900 mbar is 0.09 N/mm².
   900 mbar × 0.0001 = 0.09 N/mm²

Where it's used

Millibars are used for weather maps and barometers (sea level ≈ 1013 mbar), 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.

Millibar 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, "millibar".
• 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.