These tools ask for your components and recommend a PSU wattage. If your PC is stable, your current PSU is at least that amount.
Before we dive into the process, let's quickly discuss why checking PSU wattage is important. Your PSU is responsible for providing power to all the components in your PC, including the CPU, motherboard, graphics card, and peripherals. If your PSU is not sufficient, it can lead to:
The most reliable way to check your Power Supply Unit (PSU) wattage is to look at the on the device itself. Marketing on the box can be misleading (listing "peak" power vs. "continuous" power), but the manufacturer's label is legally required to be accurate.