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Millibar to mmHg Converter
↔ Convert mmHg to mbar instead

Common Conversions

mbar mmHg
0.01 0.0075
0.1 0.075
0.25 0.1875
0.5 0.375
1 0.75
2 1.5
5 3.75
10 7.501
25 18.752
50 37.503
100 75.006
1000 750.062

Why this conversion matters in chemistry

Vacuum ovens, freeze-dryers, and most modern vacuum-pump controllers read in mbar. Pharmacopoeial drying-loss methods, vapor-pressure tables, and a generation of chemistry instrumentation report in mmHg. The factor between them is 0.750062, which falls out of 760 mmHg = 1013.25 mbar. A 50 mbar oven setpoint becomes 37.5 mmHg on a USP method sheet; a 100 mbar rotavap pull is 75 mmHg. Multiplying by 0.750062 is what lets a modern instrument reading land on a pharmacopeia method written in legacy units.

Formula

mmHg = mbar × 0.750062

Worked Examples

1013.25 mbar = 760 mmHg

Standard atmospheric pressure expressed in both unit conventions — the calibration anchor.

1 mbar = 0.750 mmHg

The factor itself — useful for quick mental math when converting a mbar reading on the fly.

500 mbar = 375.031 mmHg

A modest reduced pressure for vacuum operations on moderately volatile solvents.

100 mbar = 75.006 mmHg

A typical rotary-evaporator working vacuum for common organic solvents at moderate bath temperatures.

Frequently Asked Questions

How do I convert millibar to mmHg?
Multiply by 0.750062. So 1013.25 mbar becomes 760 mmHg, which is one standard atmosphere in both unit conventions.
Where does this conversion show up in chemistry?
Modern vacuum gauges, freeze-dryers, and rotary-evaporator controllers read in mbar; vapor-pressure tables and pharmacopoeial methods quote in mmHg. The conversion bridges the two so a method sheet's target pressure can land on the actual gauge.
Are mbar and hPa the same?
Yes. One millibar equals one hectopascal exactly — both are 100 Pa. Meteorology has largely moved to hPa, while vacuum and chemistry instrumentation stay with mbar.