Originally Posted by wikipedia

The atmosphere on board the ISS is maintained to have a composition similar to that of the Earth's atmosphere.[67] Normal air pressure on the ISS is 101.3 kPa (14.7 psi),[68] the same as at sea level on Earth.

Originally Posted by wikipedia

Operating pressure

Generally, to supply enough oxygen for respiration, a spacesuit using pure oxygen must have a pressure of about 32.4 kPa (4.7 psi), equal to the 20.7 kPa (3.0 psi) partial pressure of oxygen in the Earth's atmosphere at sea level, plus 5.3 kPa (40 Torr) CO2 and 6.3 kPa (47 Torr) water vapor pressure, both of which must be subtracted from the alveolar pressure to get alveolar oxygen partial pressure in 100% oxygen atmospheres, by the alveolar gas equation.[2] The latter two figures add to 11.6 kPa (87 torr, 1.7 psi), which is why many modern spacesuits do not use 20.7 kPa, but 32.4 kPa (this is a slight overcorrection, as alveolar partial pressures at sea level are slightly less than the former). In spacesuits that use 20.7 kPa, the astronaut gets only 20.7 kPa - 11.7 kPa = 9.0 kPa of oxygen, which is about the alveolar oxygen partial pressure attained at an altitude of 1,860 m (6,100 ft) above sea level. This is about 78% of normal sea level pressure, about the same as pressure in a commercial passenger jet aircraft, and is the realistic lower limit for safe ordinary space suit pressurization which allows reasonable capacity for work.