mmHg to Bar Converter

mmHg to Bar

Convert mmhg (mmHg) to bar (bar). Both measure force per area, and the conversion comes up in weather, automotive, diving work.

The Formula

`` bar = mmhg × 0.00133322387415 mmhg = bar × 750.061575846 `

One mmhg is 0.001333 bar, and one bar is 750.0616 mmhg.

Conversion Table

mmHg	Bar
1 mmHg	0.001333 bar
2 mmHg	0.002666 bar
5 mmHg	0.006666 bar
10 mmHg	0.013332 bar
25 mmHg	0.033331 bar
50 mmHg	0.066661 bar
100 mmHg	0.133322 bar
500 mmHg	0.666612 bar
1,000 mmHg	1.3332 bar

The Other Direction

Bar	mmHg
1 bar	750.0616 mmHg
2 bar	1,500.12 mmHg
5 bar	3,750.31 mmHg
10 bar	7,500.62 mmHg
25 bar	18,751.54 mmHg
50 bar	37,503.08 mmHg
100 bar	75,006.16 mmHg
500 bar	375,030.79 mmHg
1,000 bar	750,061.58 mmHg

What Each Unit Is

mmHg (mmHg) — the pressure of a one-millimetre column of mercury, or 133.322 pascals. From the mercury barometer; medicine kept it after physics moved to pascals.

Bar (bar) — exactly 100,000 pascals — close to, but not exactly, one atmosphere. Introduced by meteorologist Vilhelm Bjerknes; weather maps use millibars.

A Sense of Scale

• Normal blood pressure is 120/80 mmHg
• Atmospheric pressure is 760 mmHg
• Sea-level pressure is about 1.013 bar
• Diving adds 1 bar per 10 m of depth

Precision

The factor 0.00133322387415 is rounded. For engineering work carry more digits than the table above, and round only at the end — rounding at each step compounds.

In Code

`javascript const mmHgToBar = (value) => value * 0.00133322387415; ``

Where This Conversion Comes Up

• Weather
• Automotive
• Diving
• Aviation
• HVAC

How Many Decimals Do You Need?

Rounding the factor costs accuracy, and how much depends on the factor. Converting 137 mmHg with the factor truncated at each decimal place:

Decimals kept	Factor	137 mmHg becomes	Error
0	0	0	100.0000%
1	0	0	100.0000%
2	0	0	100.0000%
3	0.001	0.137	24.9938%
4	0.0013	0.1781	2.4920%

A rule that holds for any conversion: round once, at the end. Rounding the factor and then multiplying compounds the error through every subsequent calculation, while carrying full precision and rounding the final answer does not.

The right number of significant figures is set by your input, not by the converter. If you measured mmhg to three significant figures, the answer in bar is only good to three — writing more digits claims precision the measurement never had.

Other Conversions From mmHg

The same value in every other unit this converter supports for pressure:

From	To	Unit
1 mmHg	133.322 Pa	Pascals
1 mmHg	0.133322 kPa	Kilopascals
1 mmHg	0.00131579 atm	Atmospheres
1 mmHg	0.0193368 psi	PSI

Chaining conversions works — mmhg to metres to feet gives the same answer as mmhg to feet — but each step rounds, so a chain of three conversions carries three roundings. Convert directly where a direct factor exists.