Updated at: 11-04-2023 - By: Leo Hall

You’d like to find out what kind of power supply your computer has. Please continue reading if your answer is yes, because I’m going to show you how to find out the specifics of the power supply unit that’s now installed in your computer. It’s always a good idea to be familiar with your computer’s components, especially the power supply unit (PSU), which is one of the most critical, but is frequently overlooked by most users. In the case of a pre-built PC or an old PC that you acquired, you may not be familiar with your power supply if you didn’t build it yourself. There are a few methods that you may find out about your power supply’s characteristics, so here are a few tips to get you started:

Physical Method

PSU Name / Model Number, Power/Wattage, Voltage, and Current facts can be found by opening the side panel of your computer case and looking for a sticker or label on it that provides the information you need to know about your PSU. Depending on the manufacturer, the sticker or label can be found on the sides or the top of every power supply. It’s great if you already know how to decipher the label’s technical information, but if you don’t, keep reading because I’m going to give you everything you need to know.

How to Read PSU Label / Sticker

You’ll find these information on every PSU label:

The brand and model number of the power supply unit can be found on the unit’s label. On the PSU’s label, you’ll also notice its overall wattage and the 80 Plus Certification Rating (if it has one). A Corsair RM550 power supply with 550 watts is shown below.

This is the voltage at which the power supply functions, and you need to provide it with this to operate. It is between 110V and 127V in the United States and Canada and most countries in South America, while it is between 200V and 240V in places like the United Kingdom, continental Europe, Asia, Africa, and Australia. As a result of an auto-switching mechanism, some power supplies are capable of operating at a wide range of voltages, such as 110V–240V. If you live in a location or nation where the voltage is not consistent, a physical switch can allow you to select an appropriate voltage.

The output voltage of your power source is referred to as DC (direct current). Typical ATX PSU output voltages include +3.3V, +5.5V, +12V, and +5VSB. Also known as “Rails,” the 3.3-, 5-, and 12-volt rails are the most common. Some power supplies have several 12V rails, such as Dual 12V Rail or Quad 12V Rail, depending on the PSU brand and model. There is no need for the -12V Rail in this example, as it is solely there for heritage purposes. When the PC is in standby mode to support “Power On features,” the +5VSB (standby voltage) Rail is always ON and powers the mouse, keyboard, RAM, LAN, and BIOS memory. Even when the PC is turned off (but the mains are on), it supplies a little amount of power to the BIOS and motherboard, and it is used to turn on the power supply or computer when the PC power button is pressed ON. A single 12V and a dual 12V power source are shown in the images below.

The maximum amount of current (in Amperes) that each Rail can provide is listed beneath each voltage level or Rail in the table below. If the current specified for 12V Rail is 35A, for example, your PC’s 12V rail cannot supply more than 35A of aggregate current to the different devices and components in your PC. Overloading it can lead to a failed power supply or a computer shutdown.

For a single rail or multiple rails, the combined maximum power is known as maximum power (combined). While the power of the +3.3V and 5V rails is combined, the power of the 12V rail or rails (if there are more than one) is listed individually. Voltage and current are multiplied to arrive at watts, which is the unit of power measurement. As a result, the formula for calculating power is:

wattage (W) equals voltage multiplied by amperage (I)

The total power of the PSU, stated in Watts, is the total power of the PSU. In some cases, the total combined power of all rails is added to calculate total power, while in other cases, the total combined power of the +12V Rails is used to calculate total power, because it is the most important Rail of the PSU and is used to power up to 80% to 90% of your computer components.

Find out about cables & connectors

In addition to inspecting the power supply’s connectors and wires, you can open the case to see how many there are. In an ATX 12V 2.2+ compliant power supply, you’ll typically find the following sorts of cables.

How to know in-depth information

The manufacturer’s website can be accessed after you know the name and model number of your PSU. Additionally, you can get the PSU handbook or specifications sheet from there. For example, if your PSU is a Corsair VS550, you can search this model on Google or directly go to the manufacturer’s website to learn more about its features and specs.

Refer Manual / Search Online

In the case of a pre-assembled PC, you can go to the documentation to learn about the installed power supply. If you don’t have the manual, you can also look up your PC model number on the manufacturer’s website and check out the PSU requirements for that model. Some manufacturers can modify the PSU in their later variations of the same PC model, therefore you should always check your PSU type and specifications by opening the PC case side panel.

Check power supply

Check the PSU Label

Underwriters laboratories mandate that all power supply bear a sticker indicating their power rating. A power supply’s model number and specs are always printed on a label or sticker.

You will need to open the casing of your PC and look for the written level on the PSU in order to check this label.

In order to find out the model and specifications of your power supply, you will need to remove the PSU shroud.

To remove your computer’s power supply, you may need to remove 4 or 5 screws.

Search for PC specs on the manufacturer’s website

If you have a prebuilt PC from any manufacturer, you can look up the model number on the official website.

Your computer’s product page will show you the power supply.

Find out the power supply details on its box

Check the model and specification of the pass apply on its box if you have one. Some of the power supplies come with a manual in another language. A documentation is available to help you learn more about this and how to install it on your computer.

Understanding Your Power Supply


Wattage is the most critical factor to consider when choosing a power supply. How much power your power supply unit (PSU) can offer to your system is measured in watts. Having insufficient wattage for your computer’s components will cause it to fail to start. By not delivering enough power, you could inadvertently harm some of the equipment.

RGB, overclocking, and even water cooling have an impact on watts.

Fortunately, you can use our simple PSU calculator to figure out how much power you need.


Efficiency is the next topic. PSU efficiency ‘ratings’ – typically referred to as 80+ bronze, silver, gold, and so on – can be found on the packaging. PSU efficiency is measured in terms of how quickly it can transfer power from the wall to the computer. Often, lower-quality PSUs fail to deliver adequate efficiency at the upper end of the ‘curve’.

Furthermore, the rating also tells us how safe the PSU is, so we can make an informed choice. If your PSU has no efficiency rating, the chances of it bursting into flames are much lower.


Finally, modularity is here. More specifically, modularity refers to the PSU’s physical design. The wires that connect to and from your power supply will be affected, even if they don’t change in size.

For modularity, PSUs can be categorized into three distinct groups: fully modular, semi-modular, and non-modular. ”

Cables that can’t be removed from a non-modular system are the least desired of the group. Semi-modular, on the other hand, allows for part of the wires to be removed from the design. And, you guessed it, entirely modular, with the option to detach all of their cables.


How do I know if my power supply is dying?

After disconnecting and reconnecting your hard drive and RAM to other sockets, you can determine that your power supply is failing. Computers might fail to start or lose power while they are in use.

How to test a PC power supply?

To test a power supply, you must first clear the bios memory of all overclocking data. For best results, remove the BIOS battery and leave it out of the way for at least 10 minutes before trying to restore it. After that, you can start the PC and see if everything works as it should.

How to find out what power supply you have without opening the computer?

If you don’t have the receipt from the store or the PSU box, you’ll need to know what kind of PSU you have. There aren’t any other viable alternatives.

How to tell if your power supply is bad?

If your computer’s power supply keeps shutting down while it’s running, you can count on it being a poor piece of equipment. You can test the performance of your PC’s PSU by using a different PSU to see if it’s bad or not. Most non-branded power supply are insufficient and can easily damage your computer components..

How to fix power supply overheating?

When a power supply is covered with dust or its fan is old, it overheats. The overheating problem can be solved by cleaning the PSU and replacing its fan.


It is necessary to have a power supply for your computer. Power supply failures or insufficient power delivery are to blame for the majority of computer hardware issues.

Hopefully, you’ve learnt how to find out what kind of power supply you have and how much wattage it has. ‘

You shouldn’t waste time upgrading your power supply if it’s not adequate for your PC.