Vacuum
mTorrtoatm
Convert millitorr (mTorr) to standard atmospheres (vacuum) (atm).
Factor1 mTorr = 1.315789e-6 atm
Converter
mTorr
Accepts numbers or expressions, e.g. 150 + 14.7
Result
atm
Rendered to 6 significant figures.
Formula
Formula
atm = mTorr × 1.315789e-6
Multiply any value in millitorr by 1.315789e-6 to obtain the value in standard atmospheres (vacuum).
Worked example
Convert 760000 mTorr to atm.
- 01Start with 760000 mTorr.
- 02Multiply by the conversion factor: 760000 × 1.315789e-6 = 1 atm.
Result760000 mTorr = 1 atm
Conversion table
| mTorr | atm |
|---|---|
| 1 | 1.3158e-6 |
| 2 | 2.6316e-6 |
| 5 | 6.5789e-6 |
| 10 | 1.3158e-5 |
| 20 | 2.6316e-5 |
| 50 | 6.5789e-5 |
| 100 | 0.00013158 |
| 200 | 0.00026316 |
| 500 | 0.00065789 |
| 1000 | 0.0013158 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from mTorr to atm?
1 mTorr equals 1.315789e-6 atm. To convert, multiply the value in millitorr by 1.315789e-6.
How do I convert 1 mTorr to atm?
1 mTorr = 1.31579e-6 atm. For any value, multiply by 1.315789e-6.
How do I convert atm back to mTorr?
Divide by the same factor — or equivalently, multiply by 760000. So 1 atm = 760000 mTorr.
When would I need to convert millitorr to standard atmosphere (vacuum)?
Vacuum-pressure conversions between mTorr 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).