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
  • 10
    +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
  • 1
    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

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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