The pascal (Pa) is the SI base unit of pressure, defined as one newton per square meter, used in physics, engineering, and material science. While it is the scientific standard, everyday pressures are more commonly expressed in kilopascals or megapascals because one pascal represents an extremely small pressure. One pascal equals 0.00001 bar or about 0.000145 psi.

The kilopascal (kPa) equals 1,000 pascals and is the most practical unit for everyday pressure measurements in metric countries. Tire pressure, building specifications, and weather reports in Canada, Australia, and Europe commonly use kilopascals. One kilopascal equals 0.01 bar or approximately 0.145 psi, making it a convenient middle ground between scientific and industrial scales.