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Vacuum

atmtobar

Convert standard atmospheres (vacuum) (atm) to bar (vacuum) (bar).

Factor1 atm = 1.01325 bar

Converter

atm

Accepts numbers or expressions, e.g. 150 + 14.7

Result
1.01325bar

Rendered to 6 significant figures.

Formula

Formula
bar = atm × 1.01325

Multiply any value in standard atmospheres (vacuum) by 1.01325 to obtain the value in bar (vacuum).

Worked example

Convert 1 atm to bar.

  1. 01Start with 1 atm.
  2. 02Multiply by the conversion factor: 1 × 1.01325 = 1.01325 bar.
Result1 atm = 1.01325 bar

Conversion table

atmbar
11.0132
22.0265
55.0663
1010.133
2020.265
5050.663
100101.33
200202.65
500506.63
10001013.3

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from atm to bar?
1 atm equals 1.01325 bar. To convert, multiply the value in standard atmospheres (vacuum) by 1.01325.
How do I convert 1 atm to bar?
1 atm = 1.01325 bar. For any value, multiply by 1.01325.
How do I convert bar back to atm?
Divide by the same factor — or equivalently, multiply by 0.9869233. So 1 bar = 0.986923 atm.
When would I need to convert standard atmosphere (vacuum) to bar (vacuum)?
Vacuum-pressure conversions between atm and bar are common in vacuum-chamber instrumentation, pump-down endpoint specification, semiconductor and deposition process work, freeze-drying, electron-microscopy column pressure, vacuum metallurgy and HVAC / refrigeration service. Torr, mmHg and inHg dominate manometric vacuum gauges; mbar is standard on European instruments; micron Hg and mTorr cover high-vacuum work; Pa and kPa are the SI references. This category is vacuum / instrumentation intent — dimensionally the same as pressure, but kept separate so process-pressure searches and vacuum searches stay on the right page.
Is the conversion exact?
The factor shown is precise to at least 7 significant figures. For most process-engineering work this is far better than instrument accuracy. For metrology or trade applications, refer to the relevant national standard (NIST, BIPM, ISO 80000).

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