This online tool offers a Power Supply Calculator to calculate the Power Supply Wattage for your computer base on CPU, GPU, etc.

Use an online calculator If you want to just get a rough idea of how much power your system uses, then a quick calculator can save you a lot of hassle with taking measurements.

The new Calculator in Windows 11/10 is elegant and feature-rich. Learn how to use it in the Standard, Scientific, Programmer and Conversion modes.

Microsoft's free Joulemeter utility gives you a rough estimate of a Windows system's power consumption. Plus: tips for reducing your electronics energy bill.

Oscilloscopes measure current and voltage and, through the magic of mathematics, calculate power. Unfortunately, power comes in a large number of guises: instantaneous, real, apparent, and reactive.