How many bar is 1 atmosphere?

1 atm = 1.01325 bar exactly. They are very close — 1 bar ≈ 0.9869 atm.

What is 10 atm in bar?

10 × 1.01325 = 10.1325 bar. At 10 atm (≈ 90 m depth), divers experience significant physiological effects.

What is the difference between bar and mbar?

1 bar = 1,000 mbar. Sea level atmospheric pressure ≈ 1013.25 mbar = 1.01325 bar = 1 atm.

Atmospheres to Bar Converter

1 atm = 1.01325 bar — the international standard atmosphere. Equivalent to 14.696 psi = 101.325 kPa.

Formula

bar = atm × 1.01325

Worked example

Scuba diving at 3 atm absolute pressure: 3 × 1.01325 = 3.03975 bar.

Quick reference table

atm	bar
0.5	0.506625
1	1.01325
1.5	1.519875
2	2.0265
3	3.03975
5	5.06625
10	10.1325
100	101.325

Unit definitions

Atmosphere (atm)

The standard atmosphere (atm) is defined as exactly 101,325 Pa. Used in chemistry, aviation, and diving to express pressures relative to Earth's surface.

Bar (bar)

The bar = 100,000 Pa exactly. Common in meteorology (weather maps), scuba diving, and industrial fluid systems.

Common use cases

Scuba diving depth pressure
Weather maps (mbar and bar)
Chemical reaction conditions
Gas cylinder pressures

Bar to PSI PSI to Bar Kilopascals to PSI PSI to Kilopascals Megapascals to PSI

Related guides

Common Pressure Units: PSI, Bar, kPa, atm, and MPa Explained

Pressure is force per unit area, and its units reflect the different industries and national standards that have evolved over centuries. This guide explains what each common pressure unit means, where it is used, and how to convert between them accurately.

Frequently asked questions

← All pressure converters