I think you can do current date - created date formatted as days. It would be cool however to implement moment.js (https://momentjs.com) as a plugin. It would let one automatically display date from now as some time ago, which could be seconds, minutes, hours, days etc.
I had a go at creating the plugin but gave up as I ran into some seemingly insurmountable issues - for me anyway. I couldn’t find a way to pass the necessary variables on page load, which is important. I may revisit it at some point.