🔬 Vacuum Pressure Converter
Convert vacuum pressure between Torr, mTorr, micron, Pa, kPa, mbar, bar, atm, psi, inHg, mmH2O and more. Includes absolute pressure, gauge pressure, vacuum percentage, and a comprehensive reference chart for vacuum technology applications.
What Is Vacuum Pressure?
Vacuum pressure refers to any pressure that is lower than the surrounding atmospheric pressure. In vacuum technology, pressures are typically expressed as absolute pressure — the pressure measured relative to a perfect vacuum (zero pressure).
Key concepts:
- Absolute pressure: Measured from a perfect vacuum (0 Pa). Standard atmospheric pressure is 101,325 Pa (1 atm) absolute.
- Gauge pressure: Measured relative to local atmospheric pressure. A vacuum gauge reading is negative gauge pressure.
- Vacuum percentage: The ratio of pressure reduction from atmospheric pressure, expressed as a percentage.
At standard sea level:
- 0% vacuum = 760 Torr = 1013.25 mbar = 101.325 kPa (atmospheric)
- 100% vacuum = 0 Torr = 0 mbar = 0 Pa (perfect vacuum)
Common Vacuum Pressure Units
- Torr (mmHg): The most common vacuum unit. 1 Torr = 1 mmHg = 133.322 Pa.
- mTorr (micron): One-thousandth of a Torr. Used for high vacuum measurements. 1 Torr = 1000 mTorr.
- Pascal (Pa): The SI unit of pressure. 1 Torr = 133.322 Pa.
- Millibar (mbar): Common in European vacuum specifications. 1 mbar = 100 Pa.
- Bar: 1 bar = 100,000 Pa = 1000 mbar. Standard atmospheric pressure is 1.01325 bar.
- Atmosphere (atm): 1 atm = 760 Torr = 1013.25 mbar = 101,325 Pa.
- PSI: Pounds per square inch. 1 atm = 14.696 psia.
- Inches of Mercury (inHg): Used in older vacuum gauges. 1 atm = 29.92 inHg.
How to Use This Converter
To convert vacuum pressure:
- Enter the pressure value in the input field.
- Select the unit to convert from (From Unit).
- Select the unit to convert to (To Unit).
- Click "Convert Vacuum Pressure" to see the result.
The converter will display:
- The converted value in the target unit.
- The vacuum level classification (rough, medium, high, ultra-high vacuum).
- The percentage vacuum relative to standard atmospheric pressure.
- A full conversion table showing the value in all supported units.
Why Use This Converter?
- Comprehensive units: Supports 10 vacuum pressure units including Torr, mTorr, Pa, mbar, and more.
- Vacuum level classification: Instantly see whether your pressure falls in the rough, medium, high, or ultra-high vacuum range.
- Percentage vacuum: Calculate the vacuum percentage relative to atmospheric pressure.
- Full conversion table: See the value expressed in every supported unit at once.
- Free & private: No registration, no data storage — all calculations are done in your browser.
❓ Vacuum Pressure Converter FAQ
What is the difference between absolute and gauge vacuum pressure?
Absolute pressure is measured relative to a perfect vacuum (zero). Gauge pressure is measured relative to local atmospheric pressure. Vacuum gauges typically display negative gauge pressure or a positive vacuum reading.
How many Torr is 1 atmosphere?
1 atmosphere (atm) equals 760 Torr, which is also equal to 1013.25 mbar, 101.325 kPa, or 14.696 psia.
What is the relationship between Torr and micron?
1 Torr equals 1000 mTorr (microns). So 500 microns = 0.5 Torr.
How do I convert Torr to Pa?
Multiply Torr by 133.322 to get Pascal (Pa). For example, 1 Torr = 133.322 Pa.
How do I convert mbar to Torr?
Multiply mbar by 0.75006 to get Torr. For example, 1 mbar = 0.75006 Torr.
What are the different vacuum levels?
Vacuum levels are typically classified as: Rough vacuum (760–1 Torr), Medium vacuum (1–10⁻³ Torr), High vacuum (10⁻³–10⁻⁷ Torr), Ultra-high vacuum (10⁻⁷–10⁻¹² Torr), and Extreme vacuum (below 10⁻¹² Torr).
What is the standard atmospheric pressure in vacuum units?
Standard atmospheric pressure at sea level is: 760 Torr, 1013.25 mbar, 101.325 kPa, 14.696 psia, or 29.92 inHg.
Why is vacuum pressure measured in Torr?
Torr is widely used in vacuum technology because it is a convenient unit for the pressure ranges typically encountered in vacuum systems. 1 Torr is approximately equal to 1 mmHg (millimeter of mercury).
How accurate is this converter?
This converter uses standard conversion factors from NIST and engineering references. Accuracy depends on the precision of the input values. You can adjust the decimal precision in the output.
Is this converter free?
Yes, this converter is completely free to use. No registration or personal data storage is required.