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Vacuum

inHgtomPa

Convert inches of mercury (vacuum) (inHg) to millipascals (vacuum) (mPa).

Factor1 inHg = 3386389 mPa

Converter

inHg

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

Result
3.38639e+6mPa

Rendered to 6 significant figures.

Formula

Formula
mPa = inHg × 3386389

Multiply any value in inches of mercury (vacuum) by 3386389 to obtain the value in millipascals (vacuum).

Worked example

Convert 1 inHg to mPa.

  1. 01Start with 1 inHg.
  2. 02Multiply by the conversion factor: 1 × 3386389 = 3.38639e+6 mPa.
Result1 inHg = 3.38639e+6 mPa

Conversion table

inHgmPa
13.3864e+6
26.7728e+6
51.6932e+7
103.3864e+7
206.7728e+7
501.6932e+8
1003.3864e+8
2006.7728e+8
5001.6932e+9
10003.3864e+9

Reference values rounded to 5 significant figures for display.

FAQ

What is the conversion factor from inHg to mPa?
1 inHg equals 3386389 mPa. To convert, multiply the value in inches of mercury (vacuum) by 3386389.
How do I convert 1 inHg to mPa?
1 inHg = 3.38639e+6 mPa. For any value, multiply by 3386389.
How do I convert mPa back to inHg?
Divide by the same factor — or equivalently, multiply by 2.952998e-7. So 1 mPa = 2.953e-7 inHg.
When would I need to convert inch of mercury (vacuum) to millipascal (vacuum)?
Vacuum-pressure conversions between inHg and mPa 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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