How to Calculate PSU Watts

As the name suggests, your power supply unit, or PSU, supplies power to every component in your computer, including peripheral devices that draw power from USB connections. When purchasing a new power supply unit, you should first estimate the power requirements to ensure you do not fall short -- an error that could cause system instability. Several website offer online calculators for estimating PSU requirements. Estimations are performed by entering detailed information regarding the system configuration, so be sure to have your manual or component list handy. These calculators usually offer a minimum estimate, so purchasing a PSU slightly more powerful will give you a margin of error.

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  Check out the Asus site for an easy-to-use power supply calculator, which gives you an estimate in real-time as you add components. This gives you insight as to which components tend to draw the most power. Components requiring entry into the form are minimized, so this calculator is a good choice for those uncertain of their exact computer specifications.

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  Go to Outer Vision's extreme Power Supply Calculator. This calculator is very complete, but will also give you a more accurate estimation because it takes into account just about every component in your system, with very detailed specifications for each. It even has an option to input overclock settings, which are settings designed to increase the speed of your processor beyond its native performance. The weak of heart might find this resource a little intimidating, but if you're a serious geek, you will fall in love.

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  Try out Newegg's Power Supply Calculator. This is an especially simple calculator, which is good for the novice user who may be unfamiliar with many components. You need only know the basics: CPU, motherboard classification, Memory quantity and basic type, DVD and hard drives.