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Convert Calc

Atmosphere to Millibar Converter

Enter a value to instantly convert between pressure units.

Precision4 dp

1 Atmosphere = 1013.25 Millibar

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

mbar = atm × 1013.25

One atmosphere equals 101,325 pascals, and one millibar equals 100 pascals. Dividing 101,325 by 100 gives 1,013.25 millibars per atmosphere. Weather reports worldwide use millibars as the standard pressure unit.

Source: NIST SP 811

Frequently Asked Questions

Real-World Examples

Standard sea-level pressure: 1013.25 mbar.

1 atm = 1013.25 mbar

Half atmosphere is about 507 mbar.

0.5 atm = 506.625 mbar

Two atmospheres is 2026.5 mbar.

2 atm = 2026.5 mbar

Quarter atmosphere equals 253.3 mbar.

0.25 atm = 253.3125 mbar