How many bars is 1 atmosphere?

1 standard atmosphere (atm) equals exactly 1.01325 bar. This follows from the SI definitions: 1 atm = 101,325 Pa and 1 bar = 100,000 Pa, giving 101325 / 100000 = 1.01325 bar.

How do I convert atm to bar manually?

Multiply the atmosphere value by 1.01325. For example, 2 atm × 1.01325 = 2.0265 bar. To convert bar back to atm, divide by 1.01325 (or multiply by 0.986923).

What is the difference between atm and bar?

Atmosphere (atm) is defined as the average air pressure at sea level (101,325 Pa). Bar is a metric unit equal to 100,000 Pa, chosen to be close to 1 atm for practical convenience. The bar is slightly smaller than 1 atm (about 1.3% less). Many pressure gauges and meteorological instruments use bar or millibar instead of atm.

Why is bar preferred over atm in many fields?

Bar is an accepted metric unit and is close enough to 1 atm that everyday pressures remain easy to reason about. It is the standard in meteorology, industrial process engineering, and many European countries. The IUPAC recommends bar for gas pressures in chemistry.

What is 2 atm in bar?

2 atmospheres equals 2.0265 bar. This pressure corresponds roughly to the absolute pressure at 10 meters depth underwater — a common reference in scuba diving.

Is atm or bar more accurate?

Both units are equally precise — they represent the same quantity on different scales. Accuracy depends on the measurement instrument, not the unit. For scientific work, pascal (Pa) is the SI base unit; bar and atm are both non-SI but widely accepted.

Atmospheres to Bars Converter

Name: Atmospheres to Bars Converter
Availability: InStock
Author: Nham Vu

Enter a pressure in atmospheres and get the bar equivalent instantly, with reverse bar-to-atm conversion included.

Converter

Pressure in atmospheres (atm)

Result in bars (bar)

Reverse: bars to atmospheres

Pressure in bar

Result in atm

Reference Table

Atmospheres (atm) Bars (bar)

0.1 atm 0.101325

0.5 atm 0.506625

1 atm 1.01325

1.5 atm 1.51988

2 atm 2.02650

3 atm 3.03975

5 atm 5.06625

10 atm 10.1325

15 atm 15.1988

20 atm 20.2650

50 atm 50.6625

100 atm 101.325

Formula: bar = atm × 1.01325 • atm = bar ÷ 1.01325

Summary

Enter a pressure in atmospheres and get the bar equivalent instantly, with reverse bar-to-atm conversion included.

How it works

Enter the pressure value in atmospheres (atm) in the top input field.
The bar result appears instantly with no button press needed.
Use the reverse field to convert bars back to atmospheres.
Click "Copy" next to any result to copy the value to your clipboard.
Check the reference table for common atm-to-bar values at a glance.

Use cases

Convert standard atmospheric pressure (1 atm) to bars for engineering datasheets.
Translate scuba diving depth pressures from atm to bar for dive computer calibration.
Convert chemistry experiment pressures from atm to bar for SI unit compliance.
Compare weather station readings given in atm against bar-based barometers.
Convert industrial gas cylinder specs from atm to bar for equipment compatibility.
Verify HVAC or hydraulic system pressures when switching between atm and bar units.
Convert autoclave pressure settings from atm to bar in laboratory protocols.
Cross-check altitude pressure values in atm against bar readings in aviation instruments.

Frequently Asked Questions

Last updated: 2026-07-01 · Reviewed by Nham Vu