Why is my Lumia 730 showing full phone memory even though 3gb was free?

[Windows Central Question]

why my lumia 730 is showing full phone memory even though 3gb was free ???

My lumia 730 was having 3 GB free space in phone memory but it shows only some MB left. Why is that so ???

 

[v535]

Clear IE browsing history, whatsapp chats, old sms, old email etc. to reclaim some space.