# Torr to atm Conversion

Created by Wojciech Sas, PhD
Reviewed by Steven Wooding
Last updated: Jun 05, 2023

This is the Torr to atm conversion calculator - a great tool that helps you convert torrs to atms (standard atmospheres). It also works the other way around, enabling atm to Torr conversion.

You'll find the torr's unit definition and the relationships between Torr, atm, mmHg, and many other pressure units in the article. You'll see how easy it is to perform pressure conversion, e.g. from mmHg to atm and vice versa.

What is the atmospheric pressure in torrs? How many torrs are in 1 atm? How many mmHg are in 1 atm? - If you've ever asked one of these questions, this is the right place to get the answer!

## Torr unit - Is Torr equivalent to mmHg?

Let's start from the basic definition - a torr is the unit of pressure - the quantity you can easily evaluate using Omni's pressure calculator. One Torr is precisely 1/760 of a standard atmosphere, atm. The name comes from Evangelista Torricelli, an Italian physicist and mathematician, and pioneer of pressure measurements.

Historically, the first barometers consisted of mercury (Hg) inside a vertical glass, so the natural pressure unit was mmHg (or mm Hg), a millimeter of mercury.

💡 One mmHg is the hydrostatic pressure of a 1 mm high mercury column (assuming the temperature is 32°F/0°C and the gravitational acceleration equals $9.80665 \text { m/s}^2$).

Torr and mmHg are almost the same units. So how to convert Torr to mmHg?

$1 \text{ Torr} = 0.9999998575337… \text{ mmHg}$

For completeness, here is how to move from mmHg to Torr as well:

$1\text{ mmHg} = 1.0000001424663203… \text{ Torr}$.

If we accept the accuracy of up to 6 significant figures, we can assume there is no difference between 1 Torr and 1 mmHg.

## How many torrs are in 1 atm?

According to the previous section's definition, there are exactly $760$ torrs in one standard atmosphere (as one Torr is precisely 1/760 of one atm).

We can always convert this fraction to decimal, so the atm to Torr conversion factor equals $0.00131578947…$. As you can see, using the fraction form is more convenient and prevents losing precision during computations.

The good thing is that you can also use our Torr to atm conversion as an atm to Torr conversion. Moreover, you can even change the units yourself to make it an mmHg to atm or atm to mmHg converter.

So what about mmHg to atm conversion? What are the numbers here?

$1 \text { mmHg} = 0.00131578966… \text { atm}$

or

$1 \text{ mmHg} = \text{ } ^1/_{759.99989157…} \text { atm}$

And if you want to know how many mmHg are in 1 atm, then the answer is:

$1 \text { atm} = 759.99989157…\text { mmHg}$

## How to convert Torr to atm using Torr to atm conversion?

Our tool is as simple as it could be! Assuming you want to convert 800 Torr to atm, these are the steps you should follow:

1. Type 800 in the field with the Torr unit;

2. Multiply 800 by the conversion factor, 800 Torr × 1/760 = 1.0526 atm; and

3. That's all! The answer is 1.0526 atm.

And what if you want to convert the pressure of 2.5 atmospheric pressure to torrs? Analogically:

1. Input 2.5 atm into the second field;

2. Multiply 2.5 by 760; and

Whenever you want to use technical atmospheres instead of standard ones or mmHg instead of Torr, simply change the units with just one click!

## Torr to other pressure units list

Torr, atm, or mmHg are not the only pressure units we commonly use. There are others, both metric and imperial units, such as pascals (Pa) or pounds per square inch (psi), to mention a few.

If you deal with a task of a Torr to another unit conversions, here are some of the examples (rounded to six decimal places):

• $1 \text { Torr} ≈ 133.322368 \text{ Pa}$;

• $1 \text { Torr} ≈ 1.333223 \text{ hPa}$;

• $1 \text { Torr} ≈ 0.133322 \text{ kPa}$;

• $1 \text { Torr} ≈ 0.019337 \text{ psi}$;

• $1 \text { Torr} ≈ 2.784437 \text{ lbs/ft}^2$;

• $1 \text { Torr} ≈ 0.001333 \text{ bar}$;

• $1 \text { Torr} ≈ 0.001359 \text{ atv}$;

• $1 \text { Torr} ≈ 0.039370 \text{ in Hg}$;

• $1 \text { Torr} ≈ 1.359510 \text{ cm H}_2\text O$.

Wojciech Sas, PhD
Torr to atm conversion
Torr
atm
Conversion to other units
Metric
Pa
Imperial
psi
Others
kN/m²
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