The pascal (symbol: Pa) is the SI derived unit of pressure used to quantify internal pressure, stress, Young's modulus and ultimate tensile strength. It is defined as one newton per square metre. It is named after the French polymath Blaise Pascal.

Common multiple units of the pascal are the hectopascal (1 hPa = 100 Pa) which is equal to one millibar, the kilopascal (1 kPa = 1000 Pa), the megapascal (1 MPa = 1,000,000 Pa), and the gigapascal (1 GPa = 1,000,000,000 Pa).