File Explorer doesn’t display folder sizes in the Size column due to performance concerns.

You can use a third-party app called Windhawk to install a mod to show folder sizes.

The mod works well, but may cause slight delays when loading folders in File Explorer. You can always disable or uninstall it.

You'll find a Size column in File Explorer, but it only shows the size of files, such as images and executables, and not folders. So, what's the reason behind this, and is there any way to display folder sizes in this column?

Performance is the primary reason Microsoft has not included the functionality to display folder sizes in the Size column. For example, if you have a folder on the C drive, Windows would need to scan all the contents within the folder—including subfolders and both large and small files—to calculate its total size. This process requires significant resources, which would ultimately impact Windows' performance.

The process becomes even more demanding when you open a drive with multiple folders, each containing additional subfolders. Calculating the total size of all those folders would put a heavy strain on Windows.

However, when you hover your mouse cursor over a folder, Windows displays its size after a small delay. This is possible because Windows only needs to calculate the size of that specific folder, not all the folders within the drive, making the process more feasible and efficient.