Convert between Torr and atmospheres for vacuum technology, gas systems, and laboratory applications.
Torr and atmospheres are closely related pressure units, especially in lab work, vacuum systems, and gas-law problems. Since standard atmospheric pressure is defined as 760 Torr = 1 atm, this conversion is one of the most common ways to move between a vacuum-style reading and a chemistry-style reference pressure.
This converter handles both directions and also shows the related pressure units commonly used alongside Torr and atm. It is useful when a vacuum pump, chamber, or datasheet reports pressure in Torr but the surrounding calculation or discussion uses atmospheres.
Use it when you need to move between low-pressure laboratory readings and the standard-atmosphere frame of reference without manual division by 760. It is especially handy when you are checking how far below ambient a chamber has been pulled, comparing a manometer-style reading with a gas-law formula, or restating a vacuum specification for someone who thinks in atmospheres instead of Torr. The underlying relationship is simple, but keeping the reference units side by side reduces mistakes when the pressure values become very small.
Torr is common in vacuum and laboratory equipment, while atmospheres are common in chemistry and ideal-gas discussions. This page bridges those contexts directly and keeps the standard 760 Torr = 1 atm relationship front and center. It also helps when a single experiment or datasheet mixes vacuum-style instrument readouts with atmosphere-based equations or reference tables.
ATM = Torr ÷ 760 Torr = ATM × 760 1 atm = 760 Torr
Result: 0.5 atm
380 Torr divided by 760 gives 0.5 atm, which is half of standard atmospheric pressure.
Torr is a convenient unit for vacuum and low-pressure systems because it keeps the numbers readable where atmospheres would be very small decimals. A chamber at 1 Torr is only about 0.001316 atm, which immediately shows how far below ambient pressure it is.
The unit comes from Evangelista Torricelli and the mercury-barometer tradition. Standard atmospheric pressure is 760 Torr, which is why Torr and mmHg remain common near that reference point in laboratory and medical discussion.
Use Torr when the instrument, pump, or chamber spec is written that way. Use atm when working through gas-law formulas or comparing a pressure with standard atmospheric pressure. The conversion is simple, but the preferred unit depends heavily on the field.
1 atmosphere equals exactly 760 Torr. That fixed relationship is why the conversion is so common in chemistry and vacuum work.
Divide the Torr value by 760. The result tells you what fraction of standard atmospheric pressure the system is at.
Multiply atmospheres by 760. This is useful when a formula gives pressure in atm but the instrument or chamber spec is labeled in Torr.
They are very close and often treated as equivalent in everyday practice, though they are defined slightly differently in strict metrology. For most lab and vacuum calculations, the difference is too small to matter unless the procedure demands a strict standard.
Torr is common in vacuum systems, coating equipment, mass spectrometry, and laboratory pressure measurements. It keeps low-pressure readings readable without forcing very small decimal atmosphere values.
Many gas-law formulas and constants are traditionally taught using atmospheres as the pressure unit. Using atm also makes it easy to compare a pressure with standard ambient conditions.