Want to folder size in sharepoint online as a column or any easy way ( i am user not admin)

[Hemant2004]

Want to folder size in sharepoint online as a column or any easy way

[#2]

AFAIK this is something you can only get for files, but not for folders

[#3]

@Hemant2004 

OOTB this is not possible. You will have to add logic.
One way is to develop an SPFx app that collects the "child" details for that particular folder. Another way is to create a list with all items in that library (one-off) and then using logic to determine the number of items, sizes etc..  for that folder and all other items.
The latter approach is quite an expensive operation, you will need to cater for LVT and stay below requests threshold. If you use REST queries and multiple threads you will probably get details at a rate of of say 100 items per second. If your library holds 100000 items this action will take 1000s.
One step back: why do you need this functionality? manage the contents of your library? or ...
Paul

[#4]

@Paul_HK_de_Jong Thanks for reply, we need this compare local server data size after uploading in Sharepoint server

[#5]

any simple way to make SPFx app & is it possible for non IT person

[#6]

Short answer: Nvo
SPFx is very powerful but has a serious learning curve.

[#7]

@Hemant2004 
If you want to compare metrics before and after migration please be aware that SharePoint modifies some file types during uploading. For example, an msg file will typically get 5 kB larger because SharePoint injects schema information. Office files (docx, ..) are also affected and even tiff files.
You can compare the number of items of course. That should match before and after.
There are browser-based tools that provide reporting capabilities (example) and generate a csv file with all nested content (including path, type, sizes, modified dates, encryption, etc..).
Another approach is to use PowerShell scripts. For example here.
Or perhaps use the OneDrive for Business client. Do not sync all documents to your local system but simply use the OneDrive tool to get the properties of the folders/files present.
Paul