If you built the PC yourself or bought a custom build, the most reliable way to check is to look at the sticker on the unit itself.
Identifying your PC's power supply unit (PSU) wattage is a critical step for hardware upgrades, but it isn't always as simple as checking a software menu. Unlike your CPU or GPU, most standard power supplies do not have a data connection to the motherboard, meaning Windows cannot directly "read" the total capacity of the unit. how to check your pc power supply wattage