How do I adjust my withholding after a big life change like marriage or a new baby?

Any major life event is a reason to file a fresh W-4 with your employer. Marriage changes your filing status and combined income; a new child may qualify you for the Child Tax Credit, which you claim in Step 3 to reduce withholding; a home purchase, a spouse leaving work, or a big raise all shift your numbers too. You can update your W-4 anytime, not just at open enrollment. The IRS Tax Withholding Estimator is the fastest way to see the impact and get exact entries. Updating promptly means your paychecks reflect reality for the rest of the year instead of leaving you with a surprise bill or an oversized refund the following spring.