The loss taken is limited to $3,000 a year, however if you have gains, that amount offset against the gains does not impact the $3,000.
For example, I sold some stock in 2016 and made $1,570 profit, and I had a $10,000 capital carryforward from 2015.
Then $10,000 first is reduced by the $1,570, then I claim a -$,3,000 on my return for capital loss.
My carryover to 2017 is now $5,430 ($10K -$1,570 - $3,000).