At stp amount of pressure ,to&atm

At STP (Standard Temperature and Pressure):

• Temperature (T) is $0^\circ\text{C}$ or $273.15 \text{ K}$.
• Pressure (P) is $1 \text{ atm}$ (atmosphere) or $101.325 \text{ kPa}$ (kilopascals) or $760 \text{ mmHg}$ (millimeters of mercury).

The common unit for pressure you mentioned, "atm," stands for atmospheres.