Torr to atm Conversion
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 9.80665m/s²
).
Torr
and mmHg
are almost the same units. So how to convert Torr
to mmHg
?
1 Torr = 0.9999998575337… mmHg
.
For completeness, here is how to move from mmHg
to Torr
as well:
1 mmHg = 1.0000001424663203… 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 mmHg = 0.00131578966… atm; or
 1 mmHg = ^{1}/_{759.99989157…} atm.
And if you want to know how many mmHg
are in 1 atm
, then the answer is:
1 atm = 759.99989157… 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:

Type
800
in the field with theTorr
unit; 
Multiply
800
by the conversion factor, 800 Torr × ^{1}/_{760} = 1.0526 atm; and 
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:

Input
2.5 atm
into the second field; 
Multiply
2.5
by760
; and 
Read that your value is equivalent to
1900 Torr
.
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 Torr ≈ 133.322368 Pa
;1 Torr ≈ 1.333223 hPa
;1 Torr ≈ 0.133322 kPa
;1 Torr ≈ 0.019337 psi
;1 Torr ≈ 2.784437 lbs/ft²
;1 Torr ≈ 0.001333 bar
;1 Torr ≈ 0.001359 at
;1 Torr ≈ 0.039370 in Hg
;1 Torr ≈ 1.359510 cm H₂O
.