How much unused capital losses can be used for tax purposes?

Up to $3,000 per year in capital losses ($1,500 if married filing separately) can be used to offset ordinary income (such as wages) in computing your tax liability. You can also carry forward any unused capital losses (i.e., above $3,000) to future tax years until they are used up.

How are capital gains taxed?

Unlike federal tax brackets for ordinary income, once your total income is above the relevant threshold, all of your capital gains are taxed at the higher rate (so there may be situations where you may come out ahead by earning less total income for the year).

What are capital gains?

Capital gains are profits on an investment. When you sell investments at a higher price than what you paid for them, the capital gains are "realized" and you'll owe taxes on the amount of the profit.