How to Change Partition Size in Windows, Mac, and Ubuntu

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We all face this problem. I assume you are one of us. Sometimes, your disc drive or partition runs out of space because of excessive data or you have too much space in a partition that you don’t use. Then, you want to expand or shrink the partition size which means you want to change your partition size. And, as a matter of fact, you are here because you don’t know how to change partition size. It’s easy and I will tell you.

How to Change Partition Size

When Do You Need to Change the Partition Size?

This is required to reduce pressure from one partition and balance it in terms of data and space. Usually, system C drive is the default storage location for installing programs and downloaded files. And, most users keep default settings. So, this might be very common that other partitions are full of free space and c drive is lack of space. In such condition, change partition size can be a very good solution for unbalanced free space allocation. One can shrink other partitions to get some unallocated space, and then extend C partition with the unallocated space.

Changing Partition Size in Windows

Windows has a facility or tool Disc Management by which you can change your partition size. You can extend or shrink the partition. When you want to extend partition size, you need to know one thing; the option Extend Volume is only available when the partition adjacent to the partition that you try to extend has unallocated space, otherwise the button will gray out.

Open Control Panel. In the search box, search for partition.

Changing Partition
Search for Partition

You will see Administrative tools will appear. Click Create and format hard disk partitions.

Control Panel
Administrative Tools

You will see the Disc Management page.

Disc Management Page
Disc Management

Again if you are using windows 10, you can right-click on My Computer and then click on Manage.

Disc Management  Page
Disc Management

You will find the Computer Management page. Click the Disc Management.

Computer Management Page
Computer Management

You will see the Disc Management page like before.

Shrink a partition

In the Disc Management, right click on the partition you want to shrink and from the menu, select the option Shrink Volume.

Shrink a partition
Shrink Volume

In the Shrink dialog, you have to enter the amount of volume you want to shrink. Remember that it’s not the volume of new size but the shrinking amount. As for example -If you want to shrink 20 GB, enter 20000 in the box Enter the amount of space to shrink in MB. And then click Shrink.

shrink in MB
Shrink Volume

Thus, you can shrink volume.

Extend a Partition

Like I said earlier, the Extend Volume option is only available when the partition adjacent to the partition that you try to extend has unallocated space, otherwise, the button will gray out. You might see this type of thing if you have no unallocated space adjacent to the partition.

Extend a partition of Computer
Extend a partition

If you have unallocated space, then click on Extend Volume.

Extend Volume of Partition
Extend Volume

You will see a page like this. Click Next.

Partition Wizard
Extend Volume Wizard
Extend Volume Wizard

Click Next until you get the Select disks page. Enter the amount you want to extend in MB in the box.

Finish the work as guided. Thus you can extend a partition.

Change Partition Size by Using Software

As you can see, there are limitations to the Disc Management tool. It can shrink partition but can’t extend it when there is no unallocated space adjacent to the partition. By using the software, you can overcome this limitation. There is no need for unallocated spaces to extend a partition while using the software.

There are a plenty of change partition software. Some of them are-

EaseUS Partition Master

It works almost like the Disc Management tool without that it has more features.

Download the software and launch it. To extend a partition you need some unallocated space. So, to gain the unallocated space, you have to reduce one of the partition sizes.

Select one partition and right-click on it. Select the Resize/Move Partition. To let the unallocated space behind the respective partition, move it.

Moving Partition
Resize/Move Partition
Change Partition Size
Resize/Move partition

Enter the amount of unallocated space. Click OK.

Select the partition you want to extend, right-click it. Select the option Resize/Move partition to extend it.

Resizing partition
Resize/Move partition

Click on apply. And, you are done.

MiniTool Partition Wizard

It also works same.

Download and open the software.

Right-click the partition you want to extend. Select Extend or Extend Partition.

Extending Partition
Extend Partition
Extend or Extend Partition

You have to take free space from a partition to get unallocated space. Enter the amount of free space. And click OK.

Then the target partition will be extended. Click Apply to save all operations.

Thus you can extend partition by using this software.

AOMEI Partition Assistant Standard

This software allows you to resize partition, extend partition or even merge partitions. This also works the same as the previous software.

Download and open the software.

Firstly, you have to make unallocated space. Right-click the partition from which you want to make unallocated space. Choose Resize Partition.

Resize Partition of Windows 10
Resize Partition
Resize Partition

To get it behind the partition, move the bar of unallocated space. Click OK and then Apply.

To extend the targeted partition, right click it and select Merge Partitions.

Merge Partitions with AMOEi
Merge Partitions

Select the unallocated space and click OK.

To save the operations, click Apply.

Merge Partitions
Apply Partitions

Thus, you have successfully extended a partition.

How to Change Partition Size in Ubuntu

You can extend your Ubuntu partition, shrink it or split it up; but you can’t do this while using it. To edit your partitions, you are going to need an Ubuntu live CD or a USB drive. In order to change the partition, Ubuntu live CDs include GParted partition editors.

Boot from CD or USB drive

Insert the CD or USB drive you have installed Ubuntu from on your computer and restart. Usually, the live environment should start. If it doesn’t, access your computer’s BIOS and also change its boot order. For entering BIOS, press the key that appears on your screen while computer boots, like, ESC, f1, f2, etc.

Using GParted

If on an installed Ubuntu system, the GParted partition editor isn’t present by default, then it is with the Ubuntu live environment.

To start the process, launch GParted from the Dash.

Partitions With GParted
GParted Window

If you have only one hard drive, then it’s alright. If you have multiple hard drives, select the hard drive you want to work in from the drop-down box at the right top of the GParted window.

You can’t change partitions while they are in use. Usually, partitions being used have a key icon. If a partition is mounted, unmount it by clicking the eject button which is in the file manager. Your Ubuntu live may have activated swap partition. You can deactivate it by right-clicking on it and select SwapOff.

Gparted SwapOff

To change or resize a partition, right click it and select Resize/Move.

You can enter the exact amount or can drag the handles at either side of the bar after clicking it. If the partition has free space, you can shrink it.

Your changes won’t be effective instantly. The changes you make will be queued and available in the list at the bottom of the window.

If you have shrunk a partition, you can use the unallocated space to create a new partition.

Right-click the unallocated space and choose New.

If a partition has unallocated space which is adjacent, to enlarge the partition into unallocated space, right-click it and select Resize/Move.

Enter the exact amount in the boxes or click and drag sliders to define a new partition size.

To apply the changes you made, click the green icon at the above.

After you click Apply, the saving of the changes may take some time. Don’t cancel the operation or shut down your PC until the work is done.

After performing an operation restart your computer and remove the CD or USB drive.

Change Partition Size in Mac OS

You can change the partition size in Mac OS easily by using the Disc Utility app. You can resize the mounted volume, extend or shrink partitions. Before changing the partition, you should back up your data.

Open Disc Utility. You will find it in the /Applications/Utilities/ folder. Choose the hard drive with the partition that you want to change size.

Change Partition Size in Mac
Change Partition In Mac

Go to Partition tab and select the partition you want to resize. Then, click and drag the widget in the left corner.

Change Partition Size in Mac

Change the partition as you want. Lastly, click Apply.

Thus, you can change partition size easily on Mac OS.

Frequently Asked Questions

How to resize partition in Windows Ubuntu dual boot?

You can use gparted to resize partition in Windows and Ubuntu dual boot.

What is the best partition size for dual boot?

A good rule of partition is twice the amount of RAM you have. So if you have an 8GB or RAM, your partition should be 16GB for dual boot.

Summing Up

I believe now you are not afraid of resizing partition size. I have discussed thoroughly how to change partition size in Windows, Ubuntu, and Mac OS. And none of them are difficult. There are also many softwares to do it which have been discussed also.

Changing partition size is often significant when you have not enough space in one of your disc drives. Then, you can easily change the partition size.

That’ll be all for now. All the best.

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