How to Find Out When Your Ubuntu System Was Installed

If you have inherited management of an Ubuntu server or simply lost track of time on your personal machine, you might need to know exactly when the operating system was originally installed. This information is vital for compliance auditing, hardware lifecycle management, and determining if a system is due for a complete rebuild.

Unlike Windows, which has a specific command to show the installation date, Linux doesn’t maintain a single, dedicated “install date” registry key. However, because everything in Linux is a file, you can determine the installation date by checking the creation timestamp of the earliest files created by the installer.

This guide explains two reliable methods to find out when your Ubuntu system was installed.

Method 1: Checking the Installer Logs (Easiest)

When Ubuntu is first installed, the system creates a log directory specifically for the installation process. These logs are rarely modified after the first boot, making their creation date an excellent indicator of the OS installation time.

1. Open your Ubuntu terminal.
2. Type the following command:

   ls -ld /var/log/installer

3. Press Enter.

The terminal will output the directory details. Look at the date and time listed right before the directory name (e.g., Oct 14 2021). This is the exact date the Ubuntu installer finished writing to the disk.

Note: If you upgraded your Ubuntu version (e.g., from 20.04 to 22.04), this folder’s timestamp might reflect the upgrade date rather than the original bare-metal installation date.

Method 2: Checking the Root Filesystem Creation Date (Most Accurate)

If you want the absolute, undisputed original installation date, you should check when the root filesystem (ext4) was initially formatted. The filesystem is created at the very beginning of the installation process and is never “re-created” unless the server is completely wiped.

1. First, you need to identify your root partition. Type df -h / and look at the “Filesystem” column (e.g., /dev/sda1 or /dev/nvme0n1p2).
2. Use the tune2fs command to read the filesystem superblock. Replace /dev/sda1 with your actual root partition:

   sudo tune2fs -l /dev/sda1 | grep 'Filesystem created:'

3. Press Enter. (You will need to enter your sudo password).

The output will display a precise timestamp, such as Filesystem created: Tue Oct 14 09:12:45 2021. This is the exact moment the installer formatted the drive to install Ubuntu.