How to Allocate a Hard Drive to Add Space to Another Partition in Windows 10/8/7

Brithny posted on Jul 17, 2020 to Partition Manager | How-to Articles

Windows 10 Free Space VS Unallocated Space 

Before you learn about how to allocate a hard drive, you must learn about the following things. Whenever you manage your disk space, you often come across unallocated space and free space. Both of them hold a part of the computer storage.

Unallocated space means space on a hard drive that potentially contains intact files, remnants of data, or temporary files that were created and then deleted. It is the space on a hard drive or other devices that haven't been partitioned. You can extend a partition with EaseUS partition tool if there is unallocated space on the drive.

what is unallocated space

Also read: How to Make Use of Unallocated Space in Windows 10

Free space is the vacuum of the existing partition. For example, your D drive has 300GB space, and you have used 100GB. The 200GB is the free space of the D drive. Sometimes, the free space may refer to the unusable space shown in Disk Management or the usable but unused space on an existing partition.

what is free space

When you use Disk Management or other third-party partition tools to create a partition, extend C drive, or increase drive space, you must make sure that you have unallocated space on your hard drive. The limitation is that there must be unallocated space next to the partition which you want to resize. You cannot move free space from one drive to another directly. What's more, you can only get unallocated in these ways:

  • Delete a partition to get unallocated space
  • Shrink a drive and Windows will label the unused portion of space as unallocated
  • After initializing a disk, you will see the whole disk shown as unallocated in Disk Management

Any of these ways can maximize the risk of data loss. Is there any way to directly add free space from one drive to another? Yes, all you need to do is allocate a hard drive space with EaseUS Partition Master.

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 Windows 10 is supported

How to Allocate a Hard Drive on Windows 10/8/7

EaseUS Partition Master has a feature called "Allocate Space". With it, you can directly allocate the unused space of the selected partition to another partition on the same disk. Besides, it has many highlights:

  • Merge partitions without losing data
  • Migrate operating system to SSD
  • Create/format/delete partitions
  • Convert MBR to GPT or GPT to MBR

Download EaseUS disk management tool and follow the steps to allocate free space on a hard drive. Here, I take D drive and C drive as an example.

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 Windows 10 is supported

Step 1. Right-click on the D partition with enough free space and select "Allocate Space" to allocate the free space to the C drive.

Select partition to allocate space

Step 2. Select the target partition that you need to extend, here, choose C drive. Drag the partition panel rightward to add space allocated from the source partition to the target one. Then click "OK" to confirm.

Allocate space to extend partition

Step 3. Click the "Execute Operation" button and click "Apply" to start the process of moving free space from D drive to C drive.

finish extending partition

Common Ways to Get More Free Space on a Hard Drive

You have learned the way to allocate a hard drive. How can you free up disk space? You may get free space in the following methods. 

Method 1. Clean Up Large Files

You can get free space quickly if you use reliable junk file cleanup software. EaseUS Tools M is my recommendation. Follow the steps to clean up large files:

Step 1. DOWNLOAD EaseUS Tools M for free and install it on your computer.

Step 2. Launch EaseUS Tools M in Windows PC. Select "Large File Cleanup" on the main screen.

large file cleanup - 1

Step 3. Select the drive and click "Scan" to let the program locate, find all large files on your disk.

large file cleanup - 2

Step 4. Identify and select useless large files and click "Delete" to remove those files from your PC or laptop. A message pops up and tells you this process will permanently delete the files. Click "Yes" to start the process.

large file cleanup - 3

Method 2. Empty Recycle Bin to Get Free Space

The Recycle Bin also takes up a lot of space on your hard drive. Deleted files exist in the Recycle Bin until you empty the Recycle Bin or restore the files from it. 

Step 1. Right-click on the Recycle Bin.

Step 2. Select "Empty Recycle Bin" and click "Yes".

Then, you get free space on your hard drive or SSD.

Method 3. Uninstall Unused Applications

Applications often take up a lot of disk space. You can check your programs to find out the applications which aren't used frequently and then uninstall them to gain free space.

Step 1. Open "Settings > Apps > Apps & features". 

Step 2. Select the app or game that you want to remove and click the "Uninstall" button.

Method 4. Use Disk Cleanup to Remove Temp Files

Windows has a built-in tool that enables users to delete temporary files, system files, and other unnecessary data. Using Disk Cleanup to delete various temporary files that are no longer needed, is an excellent idea to gain free space. 

Step 1. Step Open "Start", search for "Disk Cleanup" and select the top result to open the experience.

Step 2. Select files that you want to delete from C drive or other drives. Then, click the "OK" button.

remove tem files with disk cleanup


Allocating space makes it much more convenient and simpler to add free space to another partition in Windows 10/8/7 and Windows XP/Vista. There's no need to create unallocated space. Apart from resizing partition flexibly, this software can also clone a hard disk, migrate OS to SSD/HDD, convert MBR and GPT without deleting partitions, and more.

How to Allocate Disk Space Windows 10 FAQs

Here are some additional tips about allocating a hard drive on Windows 10 devices. If you still have problems, you can read on:

How do I partition a hard drive on Windows 10?

steps to partition a hard drive:

Step 1. Install and launch EaseUS Partition Master.

Step 2. Shrink the partition size.

Step 3. Create a new partition.

Step 4. Adjust the new partition size, file system, label, etc.

Step 5. Apply the changes.

What does it mean when a hard drive is unallocated?

A computer describes any physical space on a hard drive that doesn't belong to a partition as unallocated. It means that no programs can write to space. To make use of unallocated space, you need to either create a new partition using the area or expand an existing partition.

Should I leave unallocated space on a hard drive?

You do not need to do anything and use the entire disk (or at least what Windows thinks is the whole disk).

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Frequently Asked Questions

Why Choose EaseUS Partition Master?

"I've used Partition Master Professional many times to create, delete, format, move, rename, and resize partitions."PCWorld

"Partitioning tools have come a very long since the days of complicated command line utilities and EASEUS Partition Master is one of the most advanced programs available."TECH ADVISOR

"I love that the changes you make with EaseUS Partition Master Free aren't immediately applied to the disks. It makes it way easier to play out what will happen after you've made all the changes."Lifewire

Will the "Migrate OS" feature transfer the Windows system files only or the whole C drive?

To ensure that the migrated system will boot normally, the Migrate OS feature will transfer all the files in the system and the boot partitions. Generally, the boot partition is the C drive so the transfer will include all the files in C.

Does EaseUS Partition Master license apply to multiple computers?

The license of Partition Master Professional and Server editions can be used on 1 computer only, while that for for the Technician and Unlimited editions can be used on multiple machines.

What is the difference between EaseUS Partition Master Trial version and the Free version?

Free is for home users only, with most basic functions available such as partition resize and clone. While trial can help you understand how this product works and test what a full license can do on a business or server OS machine.

Will it cause any data loss after resizing the partition in EaseUS Partition Master?

Generally, it will not cause any data loss or boot issue by resizing a partition. However, in order to protect your data, we suggest that you backup the partition before resizing, in case of any unexpected situations such as power outages, computer hardware failures, etc. You can use EaseUS Todo Backup to backup the partition and its trial version is fully functioned for 30 days.

What should I prepare before resizing the partition?

On the partition that is going to be operated, there might be some files being occupied by other programs. To ensure a successful operation, we suggest that you close all the unnecessary software before resizing that partition. Otherwise, EaseUS Partition Master will detect the partition being locked by the other software and require a reboot to resize the partition under boot mode.

About EaseUS Partition Master

All-round disk & partition management software for personal and commercial use. Let it manage your storage drive: resize, format, delete, clone, convert, etc.

Video Tutorial

How to Partititon a Hard Drive on Windows 10/8/7