Standard conditions for temperature and pressure

(Redirected from STP)
At STP conditions a gas will occupy 22.4 L. [1]

Standard conditions for temperature and pressure, or STP, also referred to as standard conditions for gases, is a specific pressure and temperature that scientists use to report the properties of gases. (These are similar to NTP and SATP, see more below.) This standard makes it easier to compare different measurements for gases, such as the moles of gas in a given volume.[2] It is necessary to have a standard temperature and pressure for scientists to use in all locations around the globe in order to make meaningful comparisons between sets of data. The conditions at STP are:

  • Pressure: 105 Pascals (formerly 1 atm, but IUPAC has since changed this standard).[3]

Since the volume of a gas depends on the temperature and pressure, one mole of an ideal gas at STP conditions has a volume of 22.4 liters. This volume can be found using the ideal gas law, [math]PV=nRT[/math].

In addition to STP, there are other temperatures and pressures that can be used to compare properties of gases. Other frequently used conditions are NTP (Normal Temperature and Pressure) and SATP (Standard Ambient Temperature and Pressure). NTP is defined as a gas at 293.15 Kelvin (20°C) and 105 Pascals. And SATP is defined as a gas at 298.15 K (25°C) and 105 Pascals.

For Further Reading


  1. Gas Laws Stoichiometry - Lessons - Tes Teach", Tes Teach with Blendspace, 2019. [Online]. Available: [Accessed: 19- Nov- 2019]. This ball is apparently available for purchase!
  2. Chemistry, Rice University, 2015. [Online]. Available:
  3. IUPAC, STP [Online], Available: