Skip to main content
Convert Calc

Millibar to Atmosphere Converter

Enter a value to instantly convert between pressure units.

Precision4 dp

1 Millibar = 0.001 Atmosphere

Key Formulas

Pound per Sq. Inch → Bar

bar = psi × 0.0689476

Bar → Pound per Sq. Inch

psi = bar × 14.5038

Atmosphere → Pound per Sq. Inch

psi = atm × 14.6959

Pound per Sq. Inch → Atmosphere

atm = psi × 0.068046

Formula

atm = mbar × 0.000986923

One millibar equals 100 pascals, and one atmosphere equals 101,325 pascals. The ratio is 100 ÷ 101,325 = 0.0009869 atmospheres per millibar. This is essentially the inverse of the 1013.25 mbar per atm conversion.

Source: NIST SP 811

Frequently Asked Questions

Real-World Examples

1013.25 mbar equals exactly 1 atm.

1013.25 mbar = 1 atm

500 mbar is about 0.49 atm.

500 mbar = 0.4935 atm

1000 mbar equals 0.987 atm.

1000 mbar = 0.9869 atm

101.325 mbar is 0.1 atm.

101.325 mbar = 0.1 atm