@Mrbil
Your "taxable income" - which includes all your "ordinary" income, your long term capital gains minus your standard or itemized deduction - dictates the top LTCG tax rate you will pay.
Depending on your situation, (that is, how much of your taxable income income is "ordinary" vs. how much is LTCG), you can "progress" through the LTCG rates with some of the LTCG taxed at 0%, some at 15% and then some at 20%.
