ATM to Torr Converter

Convert between standard atmospheres (atm) and torr units of pressure with our simple calculator.

Atmosphere (atm)

Torr

What are ATM and Torr?

Standard atmosphere (atm) is a unit of pressure defined as 101,325 pascals (Pa), which is approximately the atmospheric pressure at sea level on Earth.

Torr (symbol: Torr) is a non-SI unit of pressure defined as 1/760 of an atmosphere. It was named after the Italian physicist Evangelista Torricelli, who discovered the principle of the barometer in 1643.

Conversion Formulas

ATM to Torr:

Torr = atm × 760

Example: 2 atm = 2 × 760 = 1,520 Torr

Torr to ATM:

atm = Torr ÷ 760

Example: 760 Torr = 760 ÷ 760 = 1 atm

Historical Context

The torr unit is named after Evangelista Torricelli (1608-1647), an Italian physicist and mathematician who invented the barometer. Torricelli's experiment involved filling a tube with mercury and inverting it into a dish of mercury, creating the first barometer.

One atmospheric pressure (1 atm) was found to support a column of mercury about 760 mm high at standard gravity and temperature. This observation led to the definition of the "millimeter of mercury" (mmHg) as a unit of pressure, which is very close to the modern definition of a torr.

Fun Facts and Practical Applications

Medical Applications

Blood pressure is traditionally measured in mmHg (millimeters of mercury), which is essentially equivalent to torr. A typical healthy blood pressure reading of 120/80 mmHg corresponds to 0.158/0.105 atm.

Vacuum Science

Torr is commonly used in vacuum science and technology. A "good" laboratory vacuum might be around 10^-6 Torr, which is only one-billionth of atmospheric pressure!

Atmospheric Science

The decrease in atmospheric pressure with altitude means that at the summit of Mount Everest (8,848 meters), the pressure is only about 0.34 atm or 258 Torr, making it difficult to breathe without supplemental oxygen.

Space Exploration

The pressure on Mars' surface is extremely low - only about 0.006 atm (4.56 Torr), which is less than 1% of Earth's atmospheric pressure at sea level.

Did You Know?

The pressure at the bottom of the Mariana Trench, the deepest part of the ocean, exceeds 1,086 atm (825,460 Torr) – that's over 1,000 times the pressure at sea level!