I owed a lot when I filed this year. Should I change my W-4 or start making estimated tax payments for 2026?

It depends on why you owed. If the shortfall came from a regular W-2 job, updating your Form W-4 is usually the cleanest fix. If the shortfall came from income with no withholding such as freelance work, investment income, rental income, or a side hustle, you may need estimated tax payments. Many people need both.

A simple rule of thumb:

• W-2 wages only or mostly wages: adjust your withholding with a new W-4.
• 1099, side hustle, freelance, big capital gains, Roth conversions, or other untaxed income: add quarterly estimated payments.

Why act now? The IRS expects tax to be paid during the year, not only at filing time. If you wait until next April again, you could owe interest or an underpayment penalty.

Best next step: use the IRS Tax Withholding Estimator if you have wage income. If you also have untaxed income, compare the result with the safe-harbor rules for estimated taxes. Some taxpayers purposely boost withholding late in the year because withholding is generally treated as if it was paid evenly throughout the year, which can sometimes reduce penalty exposure better than late estimated payments.

If you owed a large amount for a one-time event, like a stock sale or Roth conversion, the right answer may be a targeted estimated payment rather than permanently changing your W-4.