How to Check Power Supply Wattage Without Opening?

The purpose of this article is to provide a short and useful guide on how to check the wattage of a power supply without opening it up.

This can be done by using a handy online power supply calculator which will give you a good idea of the wattage.

Some general guidelines for determining your wattage needs are as follows:

-Estimating the power needs of the computer system is usually best done at the time of purchase. This way, if there are any changes made later down the line, they won’t have an impact on the number of watts needed.

To check power supply wattage without opening the case, the following steps should be taken. First, turn off your computer and unplug it from the wall. Next, find the number printed on the power cord’s plug. This number will correspond to a printed rating on most power supplies. You can then use this rating to determine how many watts your power supply can produce.

What Is Power Supply And How Does It Work?

The power supply is an electronic device that converts alternating current (AC) to direct current (DC). It is used in many electronic devices to convert the AC power from electric power companies into the DC power required by most electronics. The power supply can be either external or built inside the electronic device. External power supplies are usually connected directly to the mains and provide all of their own internal circuitry for converting electricity. Internal power supplies have some sort of conversion circuit already built-in. They may also contain additional circuits such as filters and regulators.

What you need

An uninterruptible power supply (UPS) is an electrical apparatus that acts as a buffer between the power grid and your computer. It can prevent unexpected power outages from causing data loss or hardware damage to the computer system. The UPS also provides protection against power spikes that can damage your computer’s hardware. You must know how many watts your computer needs to run for this task.


As with any task, there is a right way and wrong way to go about preparing for an event. When it comes to the topic of solar power, most people give little thought to how much wattage they need for the amount of power they will need on sunny days. However, with the cost of panels and installation prices dropping each year, now is as good a time as any to consider letting the sun power your home.

How to check power supply wattage without opening

When it comes to checking your power supply, there are a few different ways to do so. Some people would go so far as opening their computer case, but this can be an intimidating process for those not used to doing so. There are actually some other ways to check the wattage of your power supply without opening up your computer by using a few simple steps. The first step you should always perform when trying to determine if your power supply has enough watts is to make sure that all of your peripherals have been turned off before attempting to turn on your PC or laptop.

If any of these devices were left powered on while turning on your system, they could cause damage to your motherboard and/or hard drive. Once everything in your computer’s case is shut down, it will be time to start looking at how much wattage your power supply has available. To do this, simply open up your computer’s case and look for an indicator light located near where your power cord plugs into your wall outlet.

This light usually indicates what type of power source your computer uses: 120V AC, 240V AC, or 12VDC. The amount of watts that you need depends on the size of your monitor, speakers, CPU cooler, etc., but generally speaking, a good rule-of-thumb would be 1W per square inch of surface area. For example, if you have a 17″ laptop with a 15″ screen, then you should aim for about 150 Watts total. If you are using multiple monitors, add them together to get their combined surface area. You can also use Google Images to find images of other people’s computers so you know roughly how big they are.


The purpose of this article is to provide you with a way to check the wattage of your power supply without having to open it up. The first step is to look at the sticker which is most likely located on the side of your power supply. If you cannot find this sticker, you will need to purchase a separate device called a multimeter. You will then connect the multimeter to your power supply and measure the voltage coming out of it.

Chris Stobing
Chris Stobing is a hardware analyst at PhenomBuilts. He is a graduate of New York University. Chris brings his experience benchmarking and reviewing gadgets and PC hardware such as graphics cards, monitors, storage, and networking equipment.
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