How To Check CPU Usage In Windows, Linux, And Mac

CPU usage measures the total processor utilization across all your cores. If you check for this data, you should see a low percentage value (usually a single digit) when you aren’t running any applications. Even when running apps, the CPU usage can jump to 100%, but it should settle down to a lower value after a while.

But if your system has some issues, this value can be unreasonably high. If your system starts becoming sluggish or the fan speed increases without reason, it’s likely due to high CPU usage.

In such scenarios, you must check the current CPU usage and see if any processes are liable. Depending on your OS, various ways to check the CPU usage exist.

They offer different options, so check the methods we have provided and pick one according to your preference.

Table of Contents

How to Check CPU Usage on Windows

Most users often use GUI tools such as Task Manager or Resource Monitor to check CPU usage on Windows OS. But you can also use command-line interfaces such as PowerShell.

From the Task Manager

The Task Manager is the most common program to check CPU usage. It provides somewhat brief information on this data, which is sufficient for most users.

There are many ways to open the Task Manager. The easiest method is to press the Ctrl + Shift + Escape hotkey.

On the Processes tab,

You can see each app’s current CPU usage on the CPU column. Click on CPU to sort the list in ascending or descending order based on the CPU usage.
It also displays the total CPU usage above the column name.
If the CPU column is absent, right-click on any column name and tick CPU.

You can go to the Details tab to get more information on CPU utilization. Here,

First, right-click on a column name and pick Select columns.
Then, make sure to tick CPU and CPU time.

The CPU column shows the CPU usage across all cores for individual processes. And the CPU time shows the total processor time a process has been using since its launch.

CPU time of a process = Process uptime * CPU utilization of the process. So, if a process runs for 2 hours while using 50% CPU, its CPU time shows 1 hr.

The System Idle Process shows the free processor time on your PC. So, if its value is very high, your system is using only a small percent of the CPU processing capacity to run active processes.

You can also check the total CPU utilization for the last minute from the Task manager’s Performance tab. Clicking on CPU shows the graph for its activity along with details on usage, active processes, and threads.

Also, right-clicking on the graph and selecting Change graph to > Logical processors shows the CPU activity for all logical processors. Logical processors are the virtual cores your system uses after hyper-threading the physical ones.

Using the Resource Monitor

The Resource Monitor offers more detailed information on CPU utilization. First, open the Resource Monitor using the steps below:

Press Win + R to open Run.
Type resmon and press Enter.

Then, go to the Overview tab. Here,

You can check the CPU usage by expanding the CPU. It shows the CPU usage, CPU time, and the number of active threads for each process.
You can also enable/disable other columns by right-clicking on a column name and picking Select columns.

For more information on CPU utilization, go to the CPU tab.

Here, you can check the CPU usage and time for all active apps and services. On the right, you can also find graphs on the CPU activity for the past 60 seconds. It contains graphs for the total core activity as well as for individual cores.

Using the Performance Monitor

You can also check CPU usage using the Performance Monitor. However, people use this tool to find the most detailed information on system processes affecting the CPU, not user applications. To check the CPU usage with this program,

Enter perfmon on Run to open the Performance Monitor.
Go to Monitoring Tools > Performance Monitor.

Here you can see the real-time graph of the processor time percentage of your system. You can also add counters to track CPU usage for a single process or instance. To do so,

Click on the + (Add) button.
Select the Computer, Process, and Instance according to your choice and click Add >>.
Click OK.
Now the graph also shows the processor data for all the instances. Each has a different color for separation.

Using Command-line Interface

You can also use CLI tools to check CPU usage. In fact, using the CLI might be a better option for users familiar with such interfaces, especially if they want to use the data elsewhere.

The best Windows CLI tool you can use to check CPU usage is Windows PowerShell. It has more functionalities, and everything you can do in other terminals is also possible in PowerShell.

First, open Windows PowerShell by entering powershell on Run. Then enter the commands below according to your need.

Total CPU usage:

The command is: Get-CimInstance win32_processor | Measure-Object -Property LoadPercentage -Average
Check the value next to Average to find the CPU percentage in use.

You can also run this command with an infinite loop to check CPU load every second. The command is:
While(1) { Get-CimInstance win32_processor | Measure-Object -Property LoadPercentage -Average}

Press Ctrl + C to get out of the infinite loop.

CPU Usage for each active process:

The command you need is as follows:

Get-Counter '\Process(*)\% Processor Time' | Select-Object -ExpandProperty countersamples| Select-Object -Property instancename, cookedvalue| ? {$_.instanceName -notmatch "^(idle|_total|system)$"} | Sort-Object -Property cookedvalue -Descending| Select-Object -First 25| ft InstanceName,@{L='CPU';E={($_.Cookedvalue/100/$env:NUMBER_OF_PROCESSORS).toString('P')}} -AutoSize

The number after Select-Object -First, 25 in this case, specifies the number of instances the list will show. You can change it according to your preference.

You can also use the command with the infinite loop to check CPU usage every second.

How to Check CPU Usage on Linux

Most Linux users should already be familiar with the top command to monitor their apps and processes. But most Linux systems also contain a System Monitor GUI. This section describes how you can check CPU usage using both methods.

Using the Terminal

The top command lists all active processes with CPU load, memory usage, and other information. The list shows real-time information that refreshes constantly.

You also use the following switches along with the top function:

-i – hides idle processes (top -i)
-d – specifies the delay time in seconds for refreshing the data (top -d 10).

You can also press the following keys while top is running to perform certain tasks:

q – end the top function
p – sort processes by CPU usage
k – end process; you need to enter the PID of the process to kill
n – change the number of processes in the list

You can also use other commands like sar –u 5 and iostat to display average CPU usage. While using sar, the number 5 represents the display refresh rate. You need to press Ctrl + C to end the function.

Using the Gnome System Monitor GUI

Here’s how you can use the Gnome System Monitor on Linux to check CPU usage:

Enter gnome-system-monitor on the Terminal to open the System Monitor.
On the Processes tab, you can find individual applications’ CPU usage.
The Resources tab shows the graph for CPU usage history on all logical processors.

How to Check CPU Usage on Mac

Mac is a UNIX-based system. So the methods to check app activity are very similar to that of Linux. You can either use the Activity Monitor or the top command.

Using the Activity Monitor

The usual way to check CPU usage on Mac is through the Activity Monitor. Here are the necessary steps for the method:

Search for and open Activity Monitor using the Spotlight Search (Command + Spacebar).
The CPU tab shows the list of all active processes, their %CPU use, and CPU time.
The graph and other data below also show the total CPU load due to the system or user processes. Multi-core systems may also show total CPU usage higher than 100%.

Using the Terminal

You can also use the top command on the Mac Terminal to check your activities. The use of this command is similar to that of Linux, so check it out for more information. To end the function, press the Ctrl + C keys.