Calculator
What the mmHg Converter does
mmHg Converter: 1 mmHg = 0.13332239 kPa, so multiply a millimetre of mercury value by 0.13332239 to get kilopascal, or divide to go back. Example: 1 mmHg = 0.13332239 kPa.
The mmHg Converter takes Value, From and To and returns Result, How it was calculated and Reverse conversion. You can nudge a single number and watch the effect straight away.
Most people who open the mmHg Converter are people following a recipe or spec written elsewhere. Two industries often use the same word for slightly different quantities.
There is no account, no upload and no server round trip, because the page does the work itself.
Further down the page: what each field expects, how the result is derived, and one example worked from the defaults.
What do the mmHg Converter fields mean?
The mmHg Converter uses 3 inputs. Pre-filled inputs double as documentation: each one shows what a reasonable value looks like.
| Field | What to enter | Default |
|---|---|---|
| Value | required | 1 |
| From | choose from Pascal (Pa), Hectopascal (hPa), Kilopascal (kPa), Megapascal (MPa), Bar (bar) or Millibar (mbar) | Millimetre of mercury (mmHg) |
| To | choose from Pascal (Pa), Hectopascal (hPa), Kilopascal (kPa), Megapascal (MPa), Bar (bar) or Millibar (mbar) | Kilopascal (kPa) |
How does the mmHg Converter work?
Both units are converted through pressure's base unit (Pa), so any of the 12 units in the dropdowns can be paired in either direction without loss of accuracy.
The constants come from the SI brochure and the 1959 international yard-and-pound agreement. For quantities defined empirically rather than by treaty, the current CODATA or IAU value is used instead.
Worked example
These are the values the mmHg Converter loads by default, and the result it produces from them. This is the worked example the page starts from, reproduced here so you can check the arithmetic.
| Value | 1 |
|---|---|
| From | Millimetre of mercury (mmHg) |
| To | Kilopascal (kPa) |
| Result | 0.13332239 kPa |
|---|---|
| How it was calculated | 1 mmHg = 0.13332239 kPa, so 1 × 0.13332239 = 0.13332239 kPa |
| Reverse conversion | 7.500615758 mmHg (if you meant 1 kPa) |
Millimetres of mercury
1 millimetre of mercury (mmHg) equals exactly 133.322387415 pascals: a unit whose modern definition is based on a conventional mercury density and standard gravity, defined independently of (though numerically almost identical to) the torr.
Worth knowing
- It’s the standard unit for blood pressure worldwide. A reading of "120/80 mmHg" describes systolic over diastolic pressure, and remains the near-universal medical convention even in countries that use kPa for every other pressure measurement.
- The unit’s physical basis is genuinely mechanical: it originally referred to how many millimetres a column of mercury would rise or fall in a barometer or manometer under a given pressure, a design still visible in traditional mercury blood-pressure cuffs (sphygmomanometers).
- Mercury-based measuring instruments are increasingly being phased out for health and environmental reasons in favour of digital and aneroid devices, but the mmHg unit itself has persisted as the standard of reference even where the mercury is gone.
Definitions: BIPM SI Brochure · NIST reference on units
How to use it
- Put Value.
- Pick a value for From: the options are Pascal (Pa), Hectopascal (hPa), Kilopascal (kPa), Megapascal (MPa), Bar (bar) or Millibar (mbar).
- Pick a value for To: the options are Pascal (Pa), Hectopascal (hPa), Kilopascal (kPa), Megapascal (MPa), Bar (bar) or Millibar (mbar).
- The tool reacts immediately rather than waiting for you to finish the form.
- The results panel then shows Result, How it was calculated and Reverse conversion.
- Copy Link puts the current inputs in the URL, so bookmarking it brings the same numbers back.
What this tool does not do
- Repeated conversions compound rounding, so convert once from the original value where you can.
- Conversion factors use SI definitions; some industries use their own rounded factors.
- Defaults are illustrative starting points, not recommendations.
- Check that each figure is in the unit the label asks for; that is the most common source of a wrong result.
Frequently asked questions
Value, From and To, nothing else. Every box already holds a working value, which means a single edit is enough to get a meaningful answer.
With the values loaded when the page opens, result comes out as 0.13332239 kPa. The figure is derived from the inputs above, so it updates whenever they do.
Nothing is logged. The tool is client-side code; your data stays where you entered it.
No. There is no account, no usage cap and no trial period. The site is funded by advertising rather than by charging for the tools.
The logic is straightforward and testable; the worked example above uses the tool’s own defaults so you can verify it yourself.