[SOLVED] Any way to see a list of folders by file size easily?

My 1TB SSD at 37% full seems to be more full than I expect it to should be. Is there a GUI program, or command line for terminal, that I can use to see the size(s) of files listed, instead of having to individually check the size of each folder individually with the mouse ?

Really, the only program that I can think of that may be taking up a lot of space is my Thunderbird mail, as it saves/archives many years worth of emails. However, upon checking the invisible folder .thunderbird, it is only like 3.5 GB in size - perhaps there is another folder that Thunderbird saves all the past emails in ?

Regards,

Michael