Whether you need a replacement power adapter for your laptop because the original was damaged or lost, choosing a new one isn't that hard--in fact, you don't even have to reference the old power adapter when selecting a new one. Choosing a new laptop adapter is simply about compatibility. And finding your laptop a new partner is all about making sure that their power rating matches.

Check the laptop's model number. Use the search engine on a power adapter vendor's website to search for a compatible power adapter by your laptop's model number (see Resources).

Locate the power specifications of your laptop--usually printed on the bottom or near the laptop's power port. Locate the amperage (AMPs) and voltage (V) rating of your laptop on the power specifications list.

Match your laptop's power rating with that of the aftermarket power adapter. The voltage of the power adapter must match the voltage of the aftermarket adapter. The amp rating of the aftermarket adapter must meet or exceed the requirements of your laptop.

Select a power adapter tip from the aftermarket power adapter's kit. This fits firmly into your laptop's power port. The selected tip should not fit too loosely or need excessive force to fit the laptop's power port.