Convert millimeters of mercury to atmospheres

1 mmHg=0.001316atm

Use the converter below to change any millimeters of mercury value into atmospheres instantly — with formula, conversion table, and real-world examples.

You have

Equals

0.0013158

Conversion formula

Forward

atmospheres = millimeters of mercury × 0.001316

Reverse

millimeters of mercury = atmospheres × 760

Example: 10 mmHg × 0.001316 = 0.01316 atm.

About both units

From

Millimeter of Mercury

mmHg

The millimetre of mercury equals about 133.3 Pa — the pressure exerted by a 1 mm column of mercury at 0 °C under standard gravity. Traditionally and still used in medicine: blood pressure of 120/80 mmHg.

Real-world: Normal blood pressure: 120/80 mmHg. Atmospheric: 760 mmHg. Good vacuum: <1 mmHg.

Read full millimeter of mercury reference →

Atmosphere

atm

The standard atmosphere equals 101,325 pascals exactly — defined by CGPM in 1954. Represents average sea-level atmospheric pressure. Used in chemistry, aviation and engineering as a reference pressure.

Real-world: Sea-level pressure: 1 atm. Mount Everest summit: ~0.33 atm. Submarine at 100 m: ~11 atm.

Read full atmosphere reference →

Millimeter of Mercury to Atmosphere conversion table

Common millimeters of mercury to atmospheres values for quick reference.

Millimeter of Mercury (mmHg)	Atmosphere (atm)
1 mmHg	0.001316 atm
5 mmHg	0.006579 atm
10 mmHg	0.01316 atm
25 mmHg	0.03289 atm
50 mmHg	0.06579 atm
100 mmHg	0.1316 atm
200 mmHg	0.2632 atm
500 mmHg	0.6579 atm
1,000 mmHg	1.31579 atm
5,000 mmHg	6.57895 atm

Tips & common mistakes

Quick tips

1 mmHg ≈ 133.32 Pa ≈ 1 Torr.
760 mmHg = 1 atm.
Blood-pressure cuffs display mmHg worldwide.

Avoid these

Confusing mmHg with mmH₂O (different unit, factor of 13.6).
Mixing mmHg with torr in precise vacuum physics — they differ by one part per million.
Writing blood pressure in kPa — use mmHg for medical continuity.

Frequently asked questions

How many atmospheres in a millimeter of mercury?

One millimeter of mercury equals 0.001316 atmospheres.

How do I convert millimeters of mercury to atmospheres?

Multiply the millimeter of mercury value by 0.001316 to get the equivalent in atmospheres.

What is 100 millimeters of mercury in atmospheres?

100 millimeters of mercury equals 0.1316 atmospheres.

Is a millimeter of mercury bigger than a atmosphere?

No. 1 millimeter of mercury equals 0.001316 atmospheres, so one millimeter of mercury is smaller.

How to convert millimeters of mercury to atmospheres without a calculator?

Multiply by 0 for a quick estimate; use a calculator for precise results.

Related pressure conversions

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