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Vacuum

mmHgtoatm

Convert millimetres of mercury (vacuum) (mmHg) to standard atmospheres (vacuum) (atm).

Factor1 mmHg = 0.00131579 atm

Converter

mmHg

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

Result
1atm

Rendered to 6 significant figures.

Formula

Formula
atm = mmHg × 0.00131579

Multiply any value in millimetres of mercury (vacuum) by 0.00131579 to obtain the value in standard atmospheres (vacuum).

Worked example

Convert 760 mmHg to atm.

  1. 01Start with 760 mmHg.
  2. 02Multiply by the conversion factor: 760 × 0.00131579 = 1 atm.
Result760 mmHg = 1 atm

Conversion table

mmHgatm
10.0013158
20.0026316
50.0065789
100.013158
200.026316
500.065789
1000.13158
2000.26316
5000.65789
10001.3158

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from mmHg to atm?
1 mmHg equals 0.00131579 atm. To convert, multiply the value in millimetres of mercury (vacuum) by 0.00131579.
How do I convert 1 mmHg to atm?
1 mmHg = 0.00131579 atm. For any value, multiply by 0.00131579.
How do I convert atm back to mmHg?
Divide by the same factor — or equivalently, multiply by 759.9999. So 1 atm = 760 mmHg.
When would I need to convert millimetre of mercury (vacuum) to standard atmosphere (vacuum)?
Vacuum-pressure conversions between mmHg and atm 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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