So I've installed Ubuntu inside of Virtualbox, and I resized the window of Virtualbox to be full-size, but the Ubuntu Desktop stays the same standard size. How do I make the width of Ubuntu stretch 100% across the Virtualbox window?

  • If you don't have X (i.e. you only installed server) and don't want to install it, you need to change the resolution for grub - see those instructions here: askubuntu.com/q/54067/247661
    – Aaron Hall
    Feb 12, 2016 at 20:46

4 Answers 4


Inside the virtual machine, install the virtualbox-guest-dkms, virtualbox-guest-utils and virtualbox-guest-x11 packages. These "guest additions" include a video driver that will do what you ask, plus a mouse driver that interacts with the host system so you don't have to use the host key to "uncapture" the mouse; it just works when you're on the virtual machine's window.

There are 2 ways to do this:

  1. From the VirtualBox top menu choose Devices, Install guest additions, then wait for a mock-CD ROM to appear and run the install from there, or

  2. just type

    sudo apt-get install virtualbox-guest-dkms virtualbox-guest-utils virtualbox-guest-x11

(personal recommendation: the second (apt-get) option is very simple and quick).

  • Fantastic. I was in the process of installing the Guest Additions via the link in Virtualbox when you wrote this. However, I believe I watched as those packages were installed as well. I appreciate your help.
    – willbeeler
    Feb 15, 2012 at 15:31
  • 11
    +1 - thanks! It seems that just sudo apt-get install virtualbox-guest-dkms is required as that automatically installs the utils and x11 packages. Aug 27, 2013 at 10:34
  • This tip is really helpful. On 14.04 trusty fails to load screen vbox screen resolutions. Installing the applets fixes the bug and the X server behaves like XP inside virtualbox.
    – user43787
    Feb 20, 2014 at 8:01
  • 1
    Also note you have to give enough video RAM (more than 17 MB) to have this work
    – Claudiu
    Jul 17, 2014 at 19:28
  • 2
    Even though your answer is OLD, it still works to fix the resolution problem TODAY.... I have tried all the other options suggested by others in here and on the Internet and did not work at all... Thank you so much.......
    – ThN
    May 13, 2015 at 5:44

Shutdown your virtual box and in a terminal shell type the following command

VBoxManage setextradata global GUI/MaxGuestResolution 1366,768

the 1366,768 is just what i have set for my screen resolution on my laptop, change this to whatever your current resolution is on the machine your running. This should maximize all screens to full 100% on all guest os's

  • Cool. Thanks. I like learning different ways to do things.
    – willbeeler
    Feb 15, 2012 at 15:37
  • I tried everything else, no luck. But this answer worked perfect. Nice answer :) TX :)
    – antmw1361
    Dec 11, 2014 at 11:18
  • Just to add value to this answer, if you are using Vagrant, instead of the using the setextradata VBoxManage command, you can indirectly call it from the Vagrant file like so (see the second vb.customize): config.vm.provider "virtualbox" do |vb| vb.gui = true vb.customize ["setextradata", :id, "GUI\/LastGuestSizeHint", "1920,1080"] end Oct 8, 2022 at 6:04

Using Ubuntu inside VirtualBox on Win7 you need to reboot Ubuntu after the virtualbox-guest-dkms install before resizing would work.

  • 1
    Actually, the guest additions installer itself ask the user to reboot, no matter what host is involved. Without rebooting the screen won't re-size. Feb 18, 2014 at 19:21
  • 6
    I wasn't asked to reboot after installing guest additions via apt-get. Couldn't resize to full screen until I rebooted the guest system. +1 (host: Win 7; guest: Ubuntu 14.04 LTS)
    – km1
    Jul 2, 2014 at 19:40
  • 2
    Same here. Wouldn't resize before a reboot.
    – Lemmings19
    Jan 29, 2015 at 17:08
  • FYI: as of 18.04.2 LTS, I was not asked to reboot.
    – ysap
    Mar 2, 2019 at 1:51

Once you have installed the VirtualBox Extension Pack (scroll until you see the Extension Pack section) use host+G or the menu option under View > Auto-resize Guest Display.

NOTE: The Extension Pack version must match the version of VirtualBox.

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