mmHg to Kilopascals
Convert mmhg (mmHg) to kilopascals (kPa). Both measure force per area, and the conversion comes up in weather, automotive, diving work.
The Formula
``
kilopascals = mmhg × 0.133322387415
mmhg = kilopascals × 7.50061575846
`
One mmhg is 0.133322 kilopascals, and one kilopascal is 7.5006 mmhg.
Conversion Table
| mmHg | Kilopascals |
|---|---|
| 1 mmHg | 0.133322 kPa |
| 2 mmHg | 0.266645 kPa |
| 5 mmHg | 0.666612 kPa |
| 10 mmHg | 1.3332 kPa |
| 25 mmHg | 3.3331 kPa |
| 50 mmHg | 6.6661 kPa |
| 100 mmHg | 13.3322 kPa |
| 500 mmHg | 66.6612 kPa |
| 1,000 mmHg | 133.3224 kPa |
The Other Direction
| Kilopascals | mmHg |
|---|---|
| 1 kPa | 7.5006 mmHg |
| 2 kPa | 15.0012 mmHg |
| 5 kPa | 37.5031 mmHg |
| 10 kPa | 75.0062 mmHg |
| 25 kPa | 187.5154 mmHg |
| 50 kPa | 375.0308 mmHg |
| 100 kPa | 750.0616 mmHg |
| 500 kPa | 3,750.31 mmHg |
| 1,000 kPa | 7,500.62 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.
Kilopascals (kPa) — 1,000 pascals. The practical metric working unit for tyre and industrial pressures.
A Sense of Scale
Normal blood pressure is 120/80 mmHg- Atmospheric pressure is 760 mmHg
- Car tyres run at 220–250 kPa
- Atmospheric pressure is 101.3 kPa
Doing It in Your Head
Multiply by 2, then divide by 15. That is off by 0.01% — close enough to judge a
distance, a weight or a price, and not close enough to sign off on a drawing.
Exact Mental shortcut 1.3332 kPa 1.3333 kPa 13.3322 kPa 13.3333 kPa
Precision
The factor 0.133322387415 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 mmHgToKilopascal = (value) => value * 0.133322387415;
``
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 | 0.1 | 13.7 | 24.9938% |
| 2 | 0.13 | 17.81 | 2.4920% |
| 3 | 0.133 | 18.221 | 0.2418% |
| 4 | 0.1333 | 18.2621 | 0.0168% |
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 kilopascals is only good to three — writing more digits claims precision the measurement never had.