Convert Atmospheres to Megapascals

Formula

MPa = atm × 0.101325

or MPa = atm ÷ 9.86923266716

Derivation from SI units:

• 1 atm = 101 325 Pa (exact, by definition)
• 1 MPa = 10⁶ Pa = 1 N/mm²
• 1 atm = 101325 Pa ÷ 1000000 Pa per MPa = 0.101325 MPa

Both units are defined exactly, so the factor is exact. Atmosphere definition: atmosphere; Megapascal definition: megapascal.

Worked examples

1. A reading of 1.5 atm converts to 0.1519875 MPa.
   1.5 atm × 0.101325 = 0.1519875 MPa
2. A value of 10 atm is 1.01325 MPa.
   10 atm × 0.101325 = 1.01325 MPa

Where it's used

Atmospheres are used for chemistry and gas laws (STP and NTP conditions), while megapascals appear in concrete compressive strength (typically 20–50 MPa). Both measure pressure, stress and differential pressure (force per unit area), so the conversion is a fixed factor.

Atmosphere 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, "atmosphere, standard (atm)".
• The International System of Units (SI), 9th edition (SI Brochure), Bureau International des Poids et Mesures , Table 7, SI prefixes.

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