I think it's 300 nits, and I think they used this level through 2015 models. My 2015 model I just bought is the same brightness as my 2010 it just replaced, and it's not nearly as bright as my phone, which is 500 nits. It's really my only complaint with the 2015, would've been nice if they upped the brightness sometime between 2010 and 2015 but as with Apple, everything takes years longer than you'd expect. Screen is nice and even and cool though so I can't complain too much. I do find myself reaching for the brightness key occasionally only to find it's already maxed out.