Standard temperature and pressure, abbreviated as STP, is a commonly used term in calculations involving gases. Now we're going to say STP. The temperature is measured as either 0�C or 273.15 K.
Now we know that when we're dealing with gas calculations we tend to go with Kelvin. Now the pressure at STP is 1 atm, so just remember when you hear STP it means 273.15 K and for pressure one atmosphere.