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 megapascal (MPa) equals one million pascals and is the standard unit for high-pressure applications in structural engineering, materials testing, and hydraulic systems. Concrete strength is rated in megapascals, and steel tensile strength specifications routinely reference this unit. One megapascal equals 10 bar or approximately 145 psi, bridging metric and imperial pressure scales.