How to Create Fake Files of Any Size in Windows

Do you need a file with a size of 10 MB, 100 MB, 1 GB or 1 TB to test? Follow the following article to create one instantly.

You don’t need to download files or waste time searching for large files, you can create them easily. Sometimes you need large files quickly to test data transfer, disk performance or network capacity you have.

file size

Windows includes utilities that allow you to quickly create files of any size instantly. You don’t need a third-party app, as this feature is available in Windows 11 and older versions of Windows.

File Size

In Windows, file sizes are displayed in bytes, kilobytes (KB), megabytes (MB), gigabytes (GB) and terabytes (TB).

To convert bytes to different units such as megabytes (MB), gigabytes (GB), and terabytes (TB), you can use the following conversion factors:

1 megabyte (MB) = 1,048,576 bytes

1 gigabyte (GB) = 1,073,741,824 bytes

1 terabyte (TB) = 1,099,511,627,776 bytes

For example, if you have a size of 1,073,741,824 bytes, you can convert them to MB and GB as follows:

1,073,741,824 bytes / 1,048,576 = 1024 MB

1,073,741,824 bytes / 1,073,741,824 = 1 GB

So, 1,073,741,824 bytes equals 1024 MB or 1 GB.

Similarly, you can use individual conversion factors to convert bytes to TB if needed.

How to create a large size dummy file in Windows

Fsutil.exe is a file system utility that you can use from the command line to perform file system operations. This utility allows you to create files of any desired size.

To get started, open or run Command Prompt (CMD), then use the command with the following syntax:

fsutil file createnew filename length

For example, you would create a “dummy.txt” file with a size of 1 GB.

fsutil file createnew dummy.txt 1073741824

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