I passed my PPL skills test 03/2014, and did all my ATPL exams in 11 months whilst hour building. My CPL/ME/IR starts next month, I will be done in 09/2015.
So in total a year and a half from PPL, and that's with working 9-5 Mon-Fri too. I could have been done earlier, but I've spent the last few months saving to afford it.
As has been mentioned above, it depends on how motivated you are to do it, I would spend 4-5 hours a day after work every day studying, flying at weekends or studying again if the weather was bad.