FREE TOOL

mmHg to kPa converter

Convert blood pressure between millimeters of mercury (mmHg) and kilopascals (kPa), in either direction.

Built on the same code as the BP Log app, created by Kaustubh Dabhadkar, MD, MPH, FACC, board-certified cardiologist. Runs in your browser; nothing you type is sent anywhere.

TOOL

Convert mmHg and kPa

Type in either column. kPa is shown to one decimal; mmHg to the nearest whole number, the way monitors show it.

Top number

Bottom number

Your conversion will show here.

Common values
mmHg	kPa
80	10.7
90	12.0
120	16.0
130	17.3
140	18.7
180	24.0

This tool is educational and does not provide medical advice, diagnosis, or treatment. Its results describe numbers; they are not a diagnosis, and they are not a substitute for care from your own doctor. If you have symptoms or think you may be having a medical emergency, contact emergency services right away.

How it is calculated

One conventional millimeter of mercury is 133.322387415 pascals, or 0.133322387415 kilopascals. To go from mmHg to kPa the tool multiplies by that factor; to go back it divides. kPa values are shown to one decimal place and mmHg values to the nearest whole number, which is how monitors and guidelines report them.

The 2025 ACC/AHA categories are written in mmHg: normal is under 120/80 mmHg (about 16.0/10.7 kPa), and stage 2 starts at 140/90 mmHg (about 18.7/12.0 kPa).

Common questions

How do I convert mmHg to kPa?

Multiply by 0.133322. For example, 120 mmHg is about 16.0 kPa, and 80 mmHg is about 10.7 kPa.

How do I convert kPa to mmHg?

Divide by 0.133322, or multiply by about 7.5. For example, 18.7 kPa is about 140 mmHg.

Why is blood pressure measured in mmHg?

Early blood pressure gauges used a column of mercury, and the number of millimeters the pressure pushed it up became the unit. Most countries still report blood pressure in mmHg, and some use kPa.

RELATED GUIDES

Blood Pressure Chart: The 2025 Categories Explained

RELATED TOOLS

SOURCES

NIST Guide for the Use of the International System of Units (SI), Special Publication 811, Appendix B: Conversion factor: 1 conventional millimeter of mercury (mmHg) = 133.322 pascals

Track this automatically with BP Log.

The free iPhone app times two readings a minute apart, averages them, keeps your morning and evening numbers apart, and builds a report for your doctor.

Other ways to track: desktop, Excel and printable logs