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Millimetres of mercury to bar

Multiply millimetres of mercury by 0.00133322 to get bar.

1 mmHg = 0.00133322 barNIST SP 811
mmHg
1.0133bar

760 mmHg = 1.0133 bar

How to convert millimetres of mercury to bar

The bar is exactly 100 000 pascals (100 kPa), close to one atmosphere. The millimetre of mercury is the conventional millimetre of mercury, exactly 101325/760 pascals (about 133.322 Pa), equal to the torr.

Worked example — 760 mmHg: 760 × 0.00133322 = 1.0133 bar.

Millimetres of mercury to bar table

Common conversions.
Millimetres of mercuryBar
100 mmHg0.133322 bar
250 mmHg0.333306 bar
500 mmHg0.666612 bar
750 mmHg0.999918 bar
760 mmHg1.0133 bar
1,000 mmHg1.3332 bar
1,500 mmHg1.9998 bar
2,000 mmHg2.6664 bar
5,000 mmHg6.6661 bar

Reverse and related

About millimetres of mercury and bar

Millimetre of mercury (mmHg)

1 mmHg = 0.00133322 bar

Definition. The conventional millimetre of mercury, exactly 101325/760 pascals (about 133.322 Pa), equal to the torr

History and origin

The millimetre of mercury comes from mercury barometers, where pressure was read as the height of a mercury column. It is now fixed conventionally as one 760th of a standard atmosphere, essentially equal to the torr.

Current use

mmHg is the standard unit for blood pressure — a reading of 120/80 mmHg — and for measuring vacuums.

Source: NIST SP 811, App. B; ISO 80000-4. Exact SI values are definitional (bar = 10⁵ Pa, atm = 101 325 Pa) or derived from the pound (NIST HB 44) and standard gravity 9.80665 m/s² (psi)

Bar (bar)

1 bar = 750.0617 mmHg

Definition. Exactly 100 000 pascals (100 kPa), close to one atmosphere

History and origin

The bar was introduced in the early twentieth century by the meteorologist Vilhelm Bjerknes, defined as exactly 100 000 pascals, close to average sea-level air pressure. Its name comes from the Greek for weight.

Current use

The bar is common outside the United States for tyre pressure, diving and weather, where the closely related millibar is also used.

Source: NIST SP 811, App. B; ISO 80000-4. Exact SI values are definitional (bar = 10⁵ Pa, atm = 101 325 Pa) or derived from the pound (NIST HB 44) and standard gravity 9.80665 m/s² (psi)

Where people use this

Millimetres of mercury: blood pressure, vacuum measurement. Bar: tyre pressure outside the US, diving, weather. 750 mmHg is about 1 bar.

How we know this is right
The factor is fixed by the standards that define the units, not chosen — so it is exact, not a measurement:
1 bar = 750.0616827 mmHg, so 1 mmHg = 1 ÷ 750.0616827 = 0.00133322 bar.

Every value is carried to full double precision; the display is rounded.

Both units are defined in NIST SP 811, App. B; ISO 80000-4. Exact SI values are definitional (bar = 10⁵ Pa, atm = 101 325 Pa) or derived from the pound (NIST HB 44) and standard gravity 9.80665 m/s² (psi).

Questions people ask

How many bar is 760 mmHg?

760 mmHg, which is one atmosphere, is about 1.013 bar.

How many mmHg in a bar?

One bar is about 750 mmHg.

How many bar is 1000 mmHg?

1000 mmHg is about 1.33 bar.

All millimetre of mercury conversions