Vacuum systems, chemistry, and meteorology contexts often use torr, while other fields default to standard atmospheres, this converter switches between the two instantly, with the mmHg equivalent shown alongside.

How to use this torr to atm conversion

1. Enter a value in the Torr field to see the equivalent in standard atmospheres.
2. Or enter a value in the atm field to see the equivalent in torr, either field updates the other automatically.
3. Check the mmHg equivalent shown alongside the result.

What this converter does

The torr is a pressure unit defined so that 1 standard atmosphere equals exactly 760 torr. The standard atmosphere (atm) represents typical sea-level air pressure, used as a reference point across chemistry, physics, and engineering.

Torr and mmHg are nearly identical

Torr is nearly identical to mmHg (millimeters of mercury), differing by less than 0.001%, a difference so small it’s irrelevant for virtually all practical purposes. The torr was in fact defined to closely match the older mmHg unit while being tied to a more precise, reproducible physical definition rather than depending on the exact properties of mercury.

Frequently asked questions