Vacuum
atmtomTorr
Convert standard atmospheres (vacuum) (atm) to millitorr (mTorr).
Factor1 atm = 760000 mTorr
Converter
atm
Accepts numbers or expressions, e.g. 150 + 14.7
Result
mTorr
Rendered to 6 significant figures.
Formula
Formula
mTorr = atm × 760000
Multiply any value in standard atmospheres (vacuum) by 760000 to obtain the value in millitorr.
Worked example
Convert 1 atm to mTorr.
- 01Start with 1 atm.
- 02Multiply by the conversion factor: 1 × 760000 = 760000 mTorr.
Result1 atm = 760000 mTorr
Conversion table
| atm | mTorr |
|---|---|
| 1 | 7.6000e+5 |
| 2 | 1.5200e+6 |
| 5 | 3.8000e+6 |
| 10 | 7.6000e+6 |
| 20 | 1.52e+7 |
| 50 | 3.8e+7 |
| 100 | 7.6e+7 |
| 200 | 1.52e+8 |
| 500 | 3.8e+8 |
| 1000 | 7.6e+8 |
Reference values rounded to 5 significant figures for display.
FAQ
What is the conversion factor from atm to mTorr?
1 atm equals 760000 mTorr. To convert, multiply the value in standard atmospheres (vacuum) by 760000.
How do I convert 1 atm to mTorr?
1 atm = 760000 mTorr. For any value, multiply by 760000.
How do I convert mTorr back to atm?
Divide by the same factor — or equivalently, multiply by 1.315789e-6. So 1 mTorr = 1.31579e-6 atm.
When would I need to convert standard atmosphere (vacuum) to millitorr?
Vacuum-pressure conversions between atm 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).