Find Windows Install Date in Regedit

This article explains how to locate the exact installation date and time of the Windows operating system using the Windows Registry Editor (Regedit). You will learn the specific registry path, the values that store this data, and how to convert the raw stored timestamp into a human-readable format.

The Registry Path

The installation timestamp is located in the following path within the Registry Editor:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion

Step-by-Step Instructions

  1. Press Windows Key + R to open the Run dialog box.
  2. Type regedit and press Enter (select Yes if prompted by User Account Control).
  3. In the left navigation pane, navigate to: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion
  4. In the right pane, look for the value named InstallDate.

How to Read the Install Date

The InstallDate entry is stored as a 32-bit DWORD containing a Unix epoch timestamp (the total number of seconds that have passed since January 1, 1970).

Because this value is stored in hexadecimal or raw decimal format, it is not directly readable as a standard date and time.

Converting the Value Using PowerShell

To quickly convert the InstallDate value into a readable format without manual calculation:

  1. Right-click the Start button and select Terminal, PowerShell, or Command Prompt.
  2. Run the following command:
[datetime]'1/1/1970' + [timespan]::fromseconds((Get-ItemProperty "HKLM:\SOFTWARE\Microsoft\Windows NT\CurrentVersion").InstallDate)

This command queries the registry key and automatically converts the timestamp to your local time zone.

Additional Value: InstallTime

In modern versions of Windows 10 and Windows 11, you may also see a 64-bit QWORD value named InstallTime. This value uses the Windows FILETIME structure (the number of 100-nanosecond intervals since January 1, 1601). Like InstallDate, it represents when the current build or feature update of the operating system was installed.