What is Taxable Income?
Taxable income is the slice of your income the tax brackets are actually applied to — what's left after you've taken your deductions. It's almost always lower than what you earned.
How it works
Take your AGI, subtract either the standard deduction or your itemized deductions, then subtract the QBI deduction if you run a qualifying business. The result is taxable income, and only that figure gets run through the 10%–37% brackets.
A quick example
What people get wrong
Earning more never means your whole income jumps a bracket. Only the dollars above each threshold are taxed at the higher rate — see the tax brackets page for the full picture.