# Columns You Make Yourself: Calculated Properties

A calculated property is a column you add to Select-Object yourself, written as a hashtable with a Name for the heading and an Expression that works the value out for each object, such as a file's size in megabytes, rounded with \[math\]::Round.

![Cheat sheet for the lesson Columns You Make Yourself: Calculated Properties: A calculated property is a column you add to Select-Object yourself, written as a hashtable with a Name for the heading and an Expression that works the value out for each object, such as a file's size in megabytes…](https://fsdtrainingmedia.blob.core.windows.net/public/images/2026/11/10688151a49c44b5b6ef1ec0bf663395.webp)

- Category: PowerShell
- Level: Journeyman
- Tags: Calculated Property, hashtable, operating-system, powershell, script-block, select-object
- Updated: November 10, 2026

Source: https://www.ask-codey.com/cheat-sheets/powershell-calculated-properties-cheat-sheet