At least an 8GB stick, you won't need the full thing. Easier to get large thumbdrives then small ones these days. Answer from logicearth on reddit.com
🌐
Microsoft Learn
learn.microsoft.com › en-us › answers › questions › 5353981 › size-flash-drive-do-i-need-for-windows-11
Size Flash Drive Do I Need for Windows 11? - Microsoft Q&A
... The Windows 11 ISO file is typically around 5–6 GB, depending on the version and edition. Tools like the Windows Media Creation Tool require some extra space for formatting and bootable file configurations.
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Laptop Outlet
laptopoutlet.co.uk › blog › usb-size-windows-11-installation.html
What Size USB Do You Need for Windows 11 Installation
June 24, 2025 - Installing Windows 11 from USB? Find out the required USB size, best file format, and how to prepare your drive for a smooth setup.
🌐
Windows Forum
windowsforum.com › forums › windows help and support forums › windows news
Install Windows 11 Without a USB Drive: No-USB Methods Explained | Windows Forum
1 week ago - For blank drives, new systems, or partition‑level control: create a bootable USB (8–16 GB) or use PXE. There is no supported way to perform a complete offline partition wipe and fresh install without bootable media.
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HP
hp.com › us-en › shop › tech-takes › how-to-install-windows-11-from-usb
Install Windows 11 from USB Guide - HP® Tech Takes
May 7, 2025 - For a successful Windows 11 installation, you’ll need: A high-speed USB flash drive (16GB or larger) for faster installation times · A reliable external hard drive for backing up your data before installation · For advanced users: A bootable ...
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Quora
windows11hacks.quora.com › What-is-the-minimum-size-of-a-USB-stick-for-you-to-use-it-as-a-bootable-drive
What is the minimum size of a USB stick for you to use it as a bootable drive? - Windows 11 Hacks - Quora
Answer: Usually 8GB is enough. Most of system image install additional packages via internet during installation, or install them after reboot. So system image doesn't need to contains everything.
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EaseUS
easeus.com › data backup questions answered › how big is a windows 11 recovery usb?
How Big Is a Windows 11 Recovery USB? - EaseUS
June 30, 2025 - In other words, if the recovery drive contains system files, its size range will be 16GB-32GB. If you don't want your recovery drive to contain system files, your USB may only be 1GB. It is worth knowing that the existence of system files is very important for recovering the drive.
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H2S Media
how2shout.com › home › bootable › do you need a flash drive to install or transfer windows 11? usb vs no-usb methods explained
Do You Need a Flash Drive to Install or Transfer Windows 11? USB vs No-USB Methods Explained - H2S Media
2 weeks ago - The only catch is your hardware needs to meet Windows 11‘s requirements (TPM 2.0, Secure Boot capable, supported CPU). ... You bought a new PC without an operating system, you’re building your own machine, or you want to completely wipe your current drive and start fresh. USB required? Yes (in most cases) that will be formatted while making it bootable...
Find elsewhere
🌐
Quora
quora.com › How-do-I-install-Windows-11-to-a-64GB-3-0-USB-drive-stick
How to install Windows 11 to a 64GB 3.0 USB drive stick - Quora
Answer (1 of 3): Assyming you want to make a portable install you should purchase a USB SSD rather than a flash drive. There is a difference. After that is sorted, you'll need to workaround that Windows setup will not install to any removable storage. So, your scenario is immediately sus. What y...
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Microsoft
microsoft.com › en-ca › software-download › windows11
Download Windows 11
Make sure you have: An internet connection (internet service provider fees may apply). Sufficient data storage available on the computer, USB, or external drive you are downloading the .iso file to. A blank DVD disc with at least 8GB (and DVD burner) to create a bootable ...
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Microsoft Support
support.microsoft.com › en-us › windows › create-installation-media-for-windows-99a58364-8c02-206f-aa6f-40c3b507420d
Create installation media for Windows - Microsoft Support
A USB flash drive. A blank USB flash drive with at least 8 GB of space. It's recommended to use a blank USB flash drive because any content on the drive is deleted. For VMs, a USB flash drive isn't required. Instead, an ISO can be created for use in VMs.
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Seven Forums
sevenforums.com › installation-setup › 428199-how-many-gb-does-windows-11-require-your-usb-memory-stick.html
How many gb does windows 11 require on your usb memory stick? - Windows 7 Help Forums
I asked how many gb the installation file was. SIW2 answer in post #3 (8G) samuria gave you the link to MCT that creates a Win11 USB installation drive. Your computer specs don't meet the requirements for Win 11. There are some workarounds. Installation, Updates and Activation | Windows 11 Forum
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ASUS
asus.com › support › faq › 1039507
[Windows 11/10] How to Create and Use a USB Flash Drive Installation Media to Reinstall Windows | Official Support | ASUS Global
To use installation media for reinstalling Windows, you will need another device that can connect to the internet (if your device is unable to enter the operating system) and an empty USB flash drive (at least 8GB of space) to create the installation media for Windows.
🌐
Hp
hp.com › home › it tips › miscellaneous › how to install windows 11 from a usb drive
How to Install Windows 11 from a USB Drive
March 12, 2024 - With the Windows 11 installation file on your thumb drive, you’re almost there! The USB flash drive should have been formatted properly when you used the Windows Media Creation Tool. You do not have to use a third-party application to make it bootable.
Top answer
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21

This answer is summarized below.

  • MBR partition a 16 GB or larger flash drive to contain a FAT32 volume and an ExFAT volume.
  • Copy all the files, except sources/install.wim, from the mounted Windows ISO file to the FAT32 volume on the flash drive.
  • Copy sources/install.wim from the mounted Windows ISO file to the ExFAT volume on the flash drive.
  • Boot from the flash drive and enter a command to split the install.wim on the ExFAT volume to two files placed on the FAT32 volume.
  • The result is an USB flash drive which can be used to install Windows 11.

The steps are given next.

  1. Goto Microsoft's Download Windows 11 website and download the Windows 11 disk image (ISO) for x64 devices. In my case, the Win11_24H2_English_x64.iso file was downloaded to my Downloads folder. If your file name is different, then make the appropriate substitutions when entering the commands below.

    Insert a 16 GB or larger flash drive in an USB port on or connected to the Mac.

  2. Open a Terminal application window.

    Use the command below to determine the identifier for the USB flash drive. I my case, this was disk2. If your identifier is different, the make the appropriate substitutions in the following commands.

    diskutil list external
    

    Enter the command below to format the flash drive.

    diskutil partitiondisk disk2 mbr fat32 MYFAT32 8G exfat MyExFAT R
    

    Enter the command below to remove all extended attributes from the Windows ISO file. This will remove the quarantine placed on the file when it was downloaded.

    xattr -c ~/Downloads/Win11_24H2_English_x64.iso
    

    Enter the command below to mount the Windows 11 ISO file. In my case, the output from the command shows the file was mounted on /Volumes/CCCOMA_X64FRE_EN-US_DV9. If your folder name is different, then make the appropriate substitutions when entering the commands below.

    hdiutil attach ~/Downloads/Win11_24H2_English_x64.iso
    

    Enter the command below to change the current directory to /Volumes/CCCOMA_X64FRE_EN-US_DV9.

    cd /Volumes/CCCOMA_X64FRE_EN-US_DV9
    

    Enter the commands below to copy the files from the mounted ISO to the flash drive. Note: Since the install.wim file is very large, the cp command can take a while to complete.

    rsync -r -t --exclude=sources/install.wim . /Volumes/MYFAT32
    cp sources/install.wim /Volumes/MyExFAT
    

    Enter the commands below to unmount the Windows 11 ISO file.

    cd ~
    hdiutil detach /Volumes/CCCOMA_X64FRE_EN-US_DV9 
    

    Enter the command below to eject the flash drive. Afterwards, you can remove the flash drive.

    diskutil eject disk2
    

    You can quit the Terminal application.

  3. Using the computer where Windows is to be installed, UEFI boot from the flash drive. You should get a window similar to the one shown below. You can ignore the contents of this window.

  4. Press the shift+F10 key combination to open Command Prompt window.

    Enter the command below. From the output, determine the drive letters for the MYFAT32 and MyExFAT volumes. In my case, the was C and D respectively. If your letters are different, the make the appropriate substitutions for c:\ and d:\ when entering the dism command given below.

    echo list volume | diskpart
    

    Enter the command below to create the install.swm and install2.swm files in the c:\sources folder. Note: This command will take a while to complete.

    dism /split-image /imagefile:d:\install.wim /swmfile:c:\sources\install.swm /filesize:4000
    

    Enter the command below to close the Command Prompt window.

    exit
    
  5. Close the window. When the popup shown below appears, select "Yes". The computer will reboot.

    The next time you UEFI boot from this USB flash drive, you should encounter the following window. You then can proceed and install Windows 11.


Example of Using the Terminal Window

Last login: Sun Mar  9 09:16:57 on console
davidanderson@Davids-Mac ~ % diskutil list external
/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *15.9 GB    disk2
   1:                 DOS_FAT_32 ⁨MYFLASHDRV⁩              15.9 GB    disk2s1

davidanderson@Davids-Mac ~ % diskutil partitiondisk disk2 mbr fat32 MYFAT32 8G exfat MyExFAT R
Started partitioning on disk2
Unmounting disk
Creating the partition map
Waiting for partitions to activate
Formatting disk2s1 as MS-DOS (FAT32) with name MYFAT32
512 bytes per physical sector
/dev/rdisk2s1: 15594504 sectors in 1949313 FAT32 clusters (4096 bytes/cluster)
bps=512 spc=8 res=32 nft=2 mid=0xf8 spt=32 hds=255 hid=2048 drv=0x80 bsec=15625000 bspf=15230 rdcl=2 infs=1 bkbs=6
Mounting disk
Formatting disk2s2 as ExFAT with name MyExFAT
Volume name      : MyExFAT
Partition offset : 15628288 sectors (8001683456 bytes)
Volume size      : 15370240 sectors (7869562880 bytes)
Bytes per sector : 512
Bytes per cluster: 32768
FAT offset       : 2048 sectors (1048576 bytes)
# FAT sectors    : 2048
Number of FATs   : 1
Cluster offset   : 4096 sectors (2097152 bytes)
# Clusters       : 240096
Volume Serial #  : 67cdc143
Bitmap start     : 2
Bitmap file size : 30012
Upcase start     : 3
Upcase file size : 5836
Root start       : 4
Mounting disk
Finished partitioning on disk2
davidanderson@Davids-Mac ~ % xattr -c ~/Downloads/Win11_24H2_English_x64.iso
davidanderson@Davids-Mac ~ % hdiutil attach ~/Downloads/Win11_24H2_English_x64.iso
/dev/disk3                                              /Volumes/CCCOMA_X64FRE_EN-US_DV9
davidanderson@Davids-Mac ~ % cd /Volumes/CCCOMA_X64FRE_EN-US_DV9 
davidanderson@Davids-Mac CCCOMA_X64FRE_EN-US_DV9 % rsync -r -t --exclude=sources/install.wim . /Volumes/MYFAT32
davidanderson@Davids-Mac CCCOMA_X64FRE_EN-US_DV9 % cp sources/install.wim /Volumes/MyExFAT
davidanderson@Davids-Mac CCCOMA_X64FRE_EN-US_DV9 % cd ~
davidanderson@Davids-Mac ~ % hdiutil detach /Volumes/CCCOMA_X64FRE_EN-US_DV9
"disk3" ejected.
davidanderson@Davids-Mac ~ % diskutil eject disk2
Disk disk2 ejected
davidanderson@Davids-Mac ~ % 

Example of Using the Command Prompt Window

Microsoft Windows [Version 10.0.26100.1742]
(c) Microsoft Corporation. All rights reserved.

X:\sources>echo list volume | diskpart

Microsoft DiskPart version 10.0.26100.1150

Copyright (C) Microsoft Corporation.
On computer: MININT-NBNQP5I

DISKPART>
  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0     E                       DVD-ROM         0 B  No Media
  Volume 1     C   MYFAT32      FAT32  Removable   7629 MB  Healthy
  Volume 2     D   MyExFAT      exFAT  Removable   7505 MB  Healthy

DISKPART>
X:\sources>dism /split-image /imagefile:d:\install.wim /swmfile:c:\sources\install.swm /filesize=4000

Deployment Image Servicing and Management tool
Version: 10.0.26100.1150

The operation completed successfully.

X:\sources>exit
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3

User Dan Is Fiddling By Firelight posted the following comment.

I'm leaving this as a comment since without access to a Mac I don't feel I could write a complete answer. Instead of directly creating a bootable windows installer USB, create a Ventoy bootable USB. Once you do that you can copy bootable drive images in all the major formats on as ordinary files, and then start them from a basic menu system that Ventoy shows when it boots. It's slightly more work the first time, but as long as you don't reformat the USB it'll make any future uses much easier since it reduces the operation to a simple copy/paste. ventoy.net/en/index.html

I decided to post this answer in response to the above comment. Note that the question does not explicitly rule out posting a solution which uses third party tools.

This answer is summarized below.

  • Download Ventoy live CD image (ISO) file, then copy this file to an 8 GB or larger flash drive.
  • Boot from the flash drive and install Ventoy to the same flash drive.
  • Download the Windows 11 ISO file and copy to the flash drive.
  • Boot from the flash drive and install Windows 11. If necessary, first enroll the key in MOK manager.

The steps are given next.

  1. Goto SourceForge's Ventoy project files website and download the Ventoy live CD image (ISO) for x64 devices. In my case, the ventoy-1.1.05-livecd.iso file was downloaded to my Downloads folder. If your file name is different, then make the appropriate substitutions when entering the commands below.

    Insert an 8 GB or larger flash drive in an USB port on or connected to the Mac.

  2. Open a Terminal application window.

    Enter the command below to remove all extended attributes from the Ventoy live CD image (ISO) file. This will remove the quarantine placed on the file when it was downloaded.

    xattr -c ~/Downloads/ventoy-1.1.05-livecd.iso
    

    Use the command below to determine the identifier for the USB flash drive. I my case, this was disk2. If your identifier is different, the make the appropriate substitutions in the following commands.

    diskutil list external
    

    Enter the commands below to copy the Ventoy live CD image (ISO) file to the flash drive. Note: Using rdisk2 instead of disk2 usually results in a quicker copy.

    diskutil unmountdisk disk2
    sudo dd if=$HOME/Downloads/ventoy-1.1.05-livecd.iso bs=1m of=/dev/rdisk2
    

    Enter the command below to eject the flash drive. Afterwards, you can remove the flash drive.

    diskutil eject disk2
    
  3. Using the computer where Windows is to be installed, UEFI boot from the flash drive.

    Note
    You will need to disable Secure Boot.

    When the following Grub menu appeared, I choose the first entry, which is the default.

    Ventoy2Disk is loading completely into RAM disk. This allows the flash drive to be overwritten. In my case, to install to the same flash drive, I just needed to select "Install" button shown below, then the "OK" button in the following popups.

    After installation to the flash drive has successfully completed, the following is displayed.

    At this point, either manually shutdown the computer or reboot by closing the window. If you choose to reboot and are successful, then the following will appear.

    Shutdown the computer by pressing the F5 key, then selecting "Power" and finally selecting "Halt".

    Remove the flash drive.

  4. Goto Microsoft's Download Windows 11 website and download the Windows 11 disk image (ISO) for x64 devices. In my case, the Win11_24H2_English_x64.iso file was downloaded to my Downloads folder. If your file name is different, then make the appropriate substitutions when entering the commands below.

    Insert the same flash drive in an USB port on or connected to the Mac.

  5. Use the same or a new Terminal application window to enter the following commands.

    Enter the command below to remove all extended attributes from the Windows ISO file. This will remove the quarantine placed on the file when it was downloaded.

    xattr -c ~/Downloads/Win11_24H2_English_x64.iso
    

    Use the command below to determine the identifier for the USB flash drive. I my case, this was disk2. If your identifier is different, the make the appropriate substitutions in the following commands.

    diskutil list external
    

    Enter the command below to copy the Windows ISO file to the ExFAT formatted volume named Ventoy on the flash drive.

    cp ~/Downloads/Win11_24H2_English_x64.iso /Volumes/Ventoy
    

    Enter the command below to eject the flash drive. Afterwards, you can remove the flash drive.

    diskutil eject disk2
    
  6. If necessary, enroll key in MOK manager as described in this step.

    Using the computer where Windows is to be installed, UEFI boot from the flash drive.

    Note
    You should have Secure Boot enabled before UEFI booting from the flash drive.

    If you encounter the following display, select OK, otherwise proceed to the step 7.

    The next display should appear as shown below. Before the timer expires, press any key.

    Select Enroll key from disk, as shown below.

    Select VTOYEFI, as shown below.

    Select ENROOL_THIS_KEY_IN_MOKMANAGER.cer, as shown below.

    Select Continue, as shown below.

    Select Yes, as shown below.

    Select Reboot, as shown below.

  7. Install Windows 11.

    If you have not already done so, UEFI boot the computer where Windows is to be installed from the flash drive.

    Note
    You should have Secure Boot enabled before UEFI booting from the flash drive.

    When the display below appears, press the F5 key.

    Select Temporary Control Settings, as shown below.

    This answer assume Windows 11 is being installed on supported hardware. Normally, when booting from the Windows 11 installer, the following would be set to 0, as shown in the image below. You need to decided whether the following need to be set to 0 or 1.

    • Bypass CPU/TPM/SecureBoot check when installing Windows 11 This allows includes bypassing the 4 GB RAM check.
    • Bypass online account requirement when installing Windows 11

    When finished, press the esckey twice.

    Select Win11_24H2_English_x64.iso, as shown below.

    Select Boot in normal mode, as shown below.

    Note
    When message Press any key to boot from CD or DVD. appears, you may need to press any key.

    When the display shown below appears, proceed with the installation of Windows 11.


Example of Using the Terminal Window

Last login: Thu Mar 13 17:46:02 on ttys001
davidanderson@Davids-Mac ~ % xattr -c ~/Downloads/ventoy-1.1.05-livecd.iso
davidanderson@Davids-Mac ~ % diskutil list external
/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *15.9 GB    disk2
   1:                 DOS_FAT_32 MYFLASHDRV              15.9 GB    disk2s1

davidanderson@Davids-Mac ~ % diskutil unmountdisk disk2                                               
Unmount of all volumes on disk2 was successful
davidanderson@Davids-Mac ~ % sudo dd if=$HOME/Downloads/ventoy-1.1.05-livecd.iso bs=1m of=/dev/rdisk2 
186+1 records in
186+1 records out
195702784 bytes transferred in 4.038241 secs (48462383 bytes/sec)
davidanderson@Davids-Mac ~ % diskutil eject disk2
Disk disk2 ejected
davidanderson@Davids-Mac ~ % xattr -c ~/Downloads/Win11_24H2_English_x64.iso
davidanderson@Davids-Mac ~ % diskutil list external
/dev/disk2 (external, physical):
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:     FDisk_partition_scheme                        *15.9 GB    disk2
   1:               Windows_NTFS Ventoy                  15.8 GB    disk2s1
   2:                       0xEF                         33.6 MB    disk2s2

davidanderson@Davids-Mac ~ % cp ~/Downloads/Win11_24H2_English_x64.iso /Volumes/Ventoy 
davidanderson@Davids-Mac ~ % diskutil eject disk2
Disk disk2 ejected
davidanderson@Davids-Mac ~ % 
🌐
Eleven Forum
elevenforum.com › windows support forums › tutorials
Create Windows 11 Bootable USB Installation Media | Windows 11 Forum
July 27, 2021 - You must be signed in as an administrator to create a bootable Windows 11 installation USB. The USB flash drive needs to be at least 8 GB or larger in size.
🌐
Windows Central
windowscentral.com › microsoft › windows help
How to download Windows 11 onto a USB flash drive | Windows Central
April 27, 2024 - Under the "Volume label" field, confirm a name for the bootable media — for example, "Windows 11." In the "File system" and "Cluster size" options, do not change the default settings. Click the "Show advanced format options" button. Check the Quick format option. Check the "Create extended label and icon files" option. Click the Start button. (Optional) Check the "Remove requirement for 4GB+RAM, Secure Boot and TPM 2.0" option to create a USB ...