How to Check Power Supply Wattage on a PC

When you are trying to upgrade your PC, understanding the power supply unit (PSU) and its wattage is important. It determines how much power the PSU can deliver to other components in the system, such as the CPU, GPU, and hard drives.

A PSU that's too weak for your components can result in instability, crashes, and even damage to the components. That's why you need to ensure that your PSU is powerful enough to keep up with the high-end graphics card that you want.

But how do you check power supply wattage? In this article, you'll learn how to check PSU wattage.

Table Of Contents

What Should You Know About PSU Wattage?

If you want to build a reliable system, there are some things about PSU wattage you need to know.

1. Wattage Rating

The wattage rating is an essential aspect of a power supply unit. It represents the maximum power output that the PSU can provide to your computer components. For instance, a 650-watt PSU indicates that it can deliver 650 watts of power to your system.

2. Efficiency Rating

The efficiency rating indicates how effectively the power supply unit converts AC power on the wall into the DC power of your components. And how much energy is lost in the process.

Efficiency is often expressed as a percentage and can range from less than 80% to over 90%. The most common ratings you'll encounter are labeled as 80 PLUS, 80 PLUS Bronze, 80 PLUS Silver, 80 PLUS Gold, 80 PLUS Platinum, and 80 PLUS Titanium.

A Bronze Rated PSU with 82% efficiency, for example, will draw about 730 watts for it to output 600 watts. 18% of the original wattage is lost as heat in the conversion process.

How to Check PSU Wattage

Here's how to check power supply wattage:

1. Check the PSU Label

One of the most straightforward ways to determine your PSU wattage is to check the PSU label. The label is usually located on either side of the PSU, and it contains important information such as the wattage, model number, and brand name.

If you have a CPU case with transparent side panels, you can actually check the PSU wattage from the outside. However, opaque or tinted side panels can make it challenging to view the PSU label from the outside. In such cases, you may need to open the case to access the PSU label and check its wattage.

Some PSUs come with an LED panel that shows the current power usage and the PSU wattage. This is especially useful for those with transparent side panels, as they can check their PSU wattage without opening up their cases.

For those with tinted or opaque side panels, follow these steps to check the PSU wattage:

Remove the PC from a wall outlet.
Next, press and hold the power button for about 5 to 10 seconds. This helps remove the built-up charge from the capacitors.
Unscrew any screws on the back or side of your CPU case.
Put the screws in a metallic tray to prevent them from getting lost.
Take the panel out by sliding it outwards.
Repeat the same process to remove the other panel.
Once you remove the panel, look for the PSU. It is located on the back-top or back-bottom side of the PC.
After finding the PSU, check the labels written on it.
The PSU wattage is written in bold numbers, and the letter W is written after those numbers. You'll see something like 500W or 700W.

2. Check User Manual

If you don't have a transparent panel and you don't want to remove your opaque panel, you can check out the user manual. The PC user manual will have all the important details about its components, including the AC input, DC output, Maximum Combined Wattage, and maximum load.

The AC input: It specifies the acceptable input voltage range for your PC and how much current is required to operate at that voltage level
The DC Output: It shows the range of voltages sent to internal components like a GPU or motherboard.
Maximum Combined Wattage: It specifies the maximum combined wattage for all the components powered by the PSU.
Maximum Load: It indicates how much power each component can draw from the PSU without overloading it.

3. Connect the PSU to a Power Meter

Another way to check the PSU voltage is by connecting the PSU to a power meter. A power meter allows you to measure how much electricity your entire computer system is using. To use the watt meter, simply plug it into a wall socket. You should then connect your PC or power strip.

Unfortunately, with a power meter, it is impossible to get any further information about how much power each PC component uses. But don't worry. You can always look for a PC wattage Calculator. This tool will provide precise readings on the total amount of energy used by each component connected to your PSU.

4. Conduct an Online Search

If you do not want to open your case, you can still find out your PSU wattage by searching online. You just need to head over to the manufacturer's website. Once you are there, you should enter your PC's model number to access detailed information about its components.

However, this method may not be the most effective as manufacturers may change the PSU features and specs in some newer laptops of the same models. So, the best way is to just open the case and check the PSU wattage.

In addition, you can also search for your PC's make and model number on Google. You should then check the PSU specs on trusted websites with a reputation for accuracy and reliability. Take advantage of online forums, as they can be valuable sources of information as well.

5. Use an Online PSU Calculator

Using an online PSU calculator is a convenient and effective way to estimate your PC's power supply wattage requirement. With an online calculator, you just need to enter the components of your computer, and it will calculate the amount of power they need.

Some fantastic online tools that can calculate your PSU wattage include:

How to know if My PSU is failing

Detecting signs of a failing PSU is essential to prevent potential damage to your computer components and ensure system stability. Sometimes, it can be hard to detect a failing PSU since its symptoms may be signs of other system issues.

Here are some signs that may indicate a failing power supply unit:

Different PC components are failing repeatedly.
Your PC keeps crashing randomly.
The system refuses to start even though the fans are spinning.
PC produces extra, unusual noise.
You experience frequent blue screen crashes.

When you experience these signs and are unsure whether your PSU is the problem, you can try replacing it with another unit. If it works normally, then your PSU is faulty.

Final Words

There are several ways to check PSU wattage. Some may require you to open your PC case, while with others, you can check the power supply wattage without opening the case.

If you are not okay with opening the case, you can always start with the most convenient and non-invasive methods, such as checking the manufacturer's website or user manual.