How do I fill out the new W-4 so my withholding actually matches what I'll owe?

The redesigned W-4 no longer uses allowances. Step 1 is your filing status. Step 2 is critical if you have multiple jobs or a working spouse; check the box or use the IRS estimator so enough is withheld across paychecks. Step 3 is where you claim credits like the Child Tax Credit to reduce withholding. Step 4 lets you add other income, extra deductions, or an extra flat amount per paycheck. The most accurate approach is the IRS Tax Withholding Estimator, which tells you exactly what to enter. Aim to break even rather than getting a big refund. The W-2 Optimizer at wealthserene.com/tools/w2-optimizer can also help you dial in your paycheck withholding.