Vacuum
inHgtomTorr
Convert inches of mercury (vacuum) (inHg) to millitorr (mTorr).
Factor1 inHg = 25400.01 mTorr
Converter
inHg
Accepts numbers or expressions, e.g. 150 + 14.7
Result
mTorr
Rendered to 6 significant figures.
Formula
Formula
mTorr = inHg × 25400.01
Multiply any value in inches of mercury (vacuum) by 25400.01 to obtain the value in millitorr.
Worked example
Convert 1 inHg to mTorr.
- 01Start with 1 inHg.
- 02Multiply by the conversion factor: 1 × 25400.01 = 25400 mTorr.
Result1 inHg = 25400 mTorr
Conversion table
| inHg | mTorr |
|---|---|
| 1 | 25400 |
| 2 | 50800 |
| 5 | 1.2700e+5 |
| 10 | 2.5400e+5 |
| 20 | 5.0800e+5 |
| 50 | 1.2700e+6 |
| 100 | 2.5400e+6 |
| 200 | 5.0800e+6 |
| 500 | 1.27e+7 |
| 1000 | 2.54e+7 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from inHg to mTorr?
1 inHg equals 25400.01 mTorr. To convert, multiply the value in inches of mercury (vacuum) by 25400.01.
How do I convert 1 inHg to mTorr?
1 inHg = 25400 mTorr. For any value, multiply by 25400.01.
How do I convert mTorr back to inHg?
Divide by the same factor — or equivalently, multiply by 3.937007e-5. So 1 mTorr = 3.93701e-5 inHg.
When would I need to convert inch of mercury (vacuum) to millitorr?
Vacuum-pressure conversions between inHg and mTorr 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).