Do you mean how long does it last on your face during the day? Or how long does a bottle last with normal usage?
If you meant how long it lasts on the face, I would say that it lasts approximately 6 hours on my slightly oil-prone skin, even with a decent primer underneath. I have to touch it up if I am going to be wearing it for any longer.
If you meant how long a bottle lasts, I think it would depend on how much you are putting on. I would say that I apply a thin layer to my face, without attempting to build it up. A bottle lasts me approximately 2.5 months, applying daily.