Convert Torr (Torr) to Standard Atmospheres (atm)
1 torr equals 0.00131579 standard atmospheres.
Torr to Standard Atmosphere Converter
How to Convert Torr to Standard Atmosphere
1 torr = 0.00131579 standard atmospheres
Standard Atmosphere = Torr × 0.00131579
Example: 1 Torr × 0.00131579 = 0.00131579 atm
Reverse Conversion
To convert standard atmospheres back to torr:
- Remember, 1 standard atmosphere equals 760 torr.
- To convert 0.00131579 atm to Torr, multiply
0.00131579 x 760, resulting in1 Torr.
Common Torr to Standard Atmosphere Conversions
Torr to standard atmospheres Conversion Table
Reference table with common torr to standard atmospheres conversions. All values calculated with high precision.
Torr to Standard Atmospheres Table
0.1 to 500
Torr to Standard Atmospheres Table
1000 to 1 × 108
Standard Atmospheres to Torr Table
0.0001 to 12
Standard Atmospheres to Torr Table
1 to 100000
Definition of Torr
Torr: The Vacuum Technologist's Unit
The torr is a unit of pressure named after the Italian physicist Evangelista Torricelli, inventor of the barometer. One torr is defined as exactly 1/760 of a standard atmosphere (101,325/760 Pa ≈ 133.322 Pa). The torr is widely used in vacuum technology, physics laboratories, and high-vacuum applications where precise low-pressure measurements are needed.
Conversions to Other Units of Measurement:
- Atmosphere (atm): 1 torr equals exactly 1/760 atm. By definition, 760 torr equals exactly 1 standard atmosphere.
- Pascal (Pa): 1 torr equals approximately 133.322 pascals. This converts vacuum readings to SI units.
- Millibar (mbar): 1 torr equals approximately 1.33322 mbar. This conversion is useful for relating vacuum levels to atmospheric measurements.
- Millimeter of Mercury (mmHg): 1 torr is very close to 1 mmHg (they differ by about 0.000015%). For practical purposes, they are often used interchangeably.
- Micron (μm Hg or mTorr): 1 torr equals 1,000 millitorr (mTorr) or microns. This is commonly used for high-vacuum measurements.
The torr provides a convenient scale for vacuum measurements, where typical applications range from rough vacuum (760-1 torr) to high vacuum (10⁻³-10⁻⁹ torr).
- Definition
- Pressure unit equal to exactly 1/760 of a standard atmosphere.
- Exact factor
- 1 Torr = 101,325/760 Pa = 133.32236842... Pa
- Common equivalents
- 760 Torr = 1 atm (exact by definition)
- 1 Torr ≈ 1 mmHg
- 1 Torr ≈ 1.33322 mbar
- Sources
Definition of Standard Atmosphere
Atmosphere: Standard Atmospheric Pressure
The standard atmosphere (atm) is a unit of pressure defined as exactly 101,325 pascals. It represents the typical atmospheric pressure at sea level under standard conditions. The atmosphere is commonly used as a reference point for pressure measurements and is particularly important in chemistry, physics, and meteorology for defining standard conditions.
Conversions to Other Units of Measurement:
- Pascal (Pa): 1 atmosphere equals exactly 101,325 pascals. This is the definition of the standard atmosphere.
- Bar: 1 atmosphere equals exactly 1.01325 bar. The bar was designed to be close to atmospheric pressure. For example, 2 atm equals 2.0265 bar.
- PSI: 1 atmosphere equals approximately 14.6959 psi. This is a fundamental conversion for many applications. Standard atmospheric pressure is often approximated as 14.7 psi.
- Torr: 1 atmosphere equals exactly 760 torr. This relationship comes from the original definition of the torr based on mercury column height.
- Millibar (mbar): 1 atmosphere equals exactly 1013.25 millibar. This is commonly used in meteorology for weather maps.
The atmosphere provides an intuitive reference for pressure, being directly related to the air pressure we experience daily at sea level.
- Definition
- Standard unit of atmospheric pressure defined as exactly 101,325 pascals.
- Exact factor
- 1 atm = 101,325 Pa (exact)
- Common equivalents
- 1 atm = 760 torr (exact by definition)
- 1 atm = 1.01325 bar (exact)
- 1 atm ≈ 14.6959 psi
- Sources
About the Torr
Facts & Uses
- 1 torr = 1/760 of a standard atmosphere exactly = 101325/760 Pa ≈ 133.322 Pa. Numerically equal to 1 mmHg under standard conditions.
- Named after Evangelista Torricelli (1608-1647), the inventor of the mercury barometer in 1643.
- Standard in vacuum technology: ultra-high vacuum systems measured in milli-torr or micro-torr; semiconductor manufacturing uses torr for chamber pressures.
- Still common in medical contexts for blood pressure (interchangeable with mmHg) and partial pressures of gases in respiratory physiology.
Curiosities
- The torr is essentially equivalent to mmHg at standard conditions, but the torr is defined exactly while mmHg depends on mercury density and gravity.
- Torricelli's 1643 experiment was the first scientific demonstration of atmospheric pressure — a glass tube filled with mercury inverted into a basin showed the column standing at ~760 mm.
- A perfect vacuum would be 0 torr; the lowest practical vacuum in commercial systems is about 10⁻¹¹ torr — used in surface science and accelerators.
- Approximate equivalents: 760 torr = 1 atm; 1 torr ≈ 133 Pa ≈ 0.0193 psi.
Sources
About the Standard Atmosphere
Facts & Uses
- 1 atm = 101,325 Pa exactly — the standard reference for sea-level atmospheric pressure, defined by the 10th CGPM in 1954.
- Used as a reference pressure in chemistry, physics, and meteorology. Many gas calculations use atm as the unit of choice.
- Defines standard temperature and pressure (STP) in older chemistry conventions: 0 °C and 1 atm. (IUPAC since 1982 uses 100 kPa instead.)
- Reference for scuba and diving tables: 1 atm of pressure increase for every 10 m of seawater (or 33 ft).
Curiosities
- The standard atmosphere is an arbitrary reference — actual sea-level pressure varies daily by ±50 hPa based on weather systems.
- The 10th CGPM (1954) chose 101,325 Pa exactly to align with the historical definition based on a 760 mm column of mercury at 0 °C and standard gravity.
- The pressure at the top of Mount Everest is about 0.33 atm (33.7 kPa) — only one-third of sea level, which is why supplemental oxygen is essential above 8000 m.
- Approximate equivalents: 1 atm = 14.696 psi = 1.01325 bar = 760 mmHg = 760 torr.
Sources
Frequently Asked Questions
How many standard atmospheres are in one torr?
One torr equals 0.00131579 standard atmospheres. To convert, multiply the torr value by 0.00131579. For the reverse, divide the standard atmosphere value by 0.00131579 (or multiply by 760).
What is 1140 torr in standard atmospheres?
1140 torr = 1 12 standard atmospheres. This is one of the most commonly searched conversions for this pair.
How precise is the torr-to-standard atmosphere conversion?
The factor 0.00131579 is accurate to 6 significant figures, derived from international measurement standards. Our calculator uses full precision internally.
Looking for the reverse? Convert Standard Atmosphere to Torr
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