Millimeters of Mercury to Kilopascals Converter

Home monitors, hospital records and research papers do not all use the same pressure unit. Some show millimetres of mercury and some show kilopascals, and you may need to line up two sets of numbers. Convert the two parts of a reading separately, because the input takes one number at a time. If you type the whole reading as 120/80, the field shows that it couldn't read the number, so enter 120 and 80 one at a time.

This page converts units only. It does not judge whether a reading is high or low. Questions about a reading belong with whoever provides your care.

One mmHg is 0.133322 kPa here, which is extremely close to 2/15. So dividing by 7.5 gets you within 0.009% of the converter. In practice:

• 90 mmHg ÷ 7.5 = 12 kPa (converter: 11.999).
• 150 mmHg ÷ 7.5 = 20 kPa.
• For the reverse, multiply kPa by 7.5: 16 kPa × 7.5 = 120 mmHg.

Multiplying by 0.13 is easier to remember but runs 2.5% low, which is about 0.4 kPa at 120 mmHg.

Outside medicine, mmHg shows up on older barometers, vacuum pump specs and lab manometers, while modern data sheets favour kPa. 760 mmHg converts to 101.33 kPa and 750 mmHg to 99.9918 kPa. The pressure menu also includes Pa, bar, psi and atm, so you can go straight from mmHg to whichever unit a spec sheet uses without a second step.

A kilopascal is about 7.5 times larger than a millimetre of mercury, so one decimal of kPa is a coarser step than one whole mmHg: 0.1 kPa is 0.75006 mmHg. This matters if you convert a rounded kPa value back. 16.0 kPa returns 120.01 mmHg, close to where you started, but 10.7 kPa returns 80.2566 mmHg, not 80. If you need to get back to the original numbers, keep two decimals of kPa or keep the original mmHg values.