What are the estimated tax payment due dates for 2026 and how do I avoid the underpayment penalty?

If you are self-employed, a freelancer, investor, or have any income without withholding, you are generally required to make quarterly estimated tax payments to the IRS. Failing to pay enough can trigger an underpayment penalty, even if you pay the full amount when you file.

2026 Estimated Tax Due Dates:

Note: If a due date falls on a weekend or federal holiday, it shifts to the next business day.

The Safe Harbor Rules (how to avoid the penalty):

You can avoid the underpayment penalty entirely by meeting any one of these three safe harbors:

• 90% of current-year tax: Pay at least 90% of what you will owe for 2026 across your four quarterly payments.
• 100% of prior-year tax: Pay at least 100% of what you owed on your 2025 return (regardless of what you actually owe in 2026). This is the easiest safe harbor for most people -- just divide last year's total tax by 4 and pay that each quarter.
• 110% rule for higher earners: If your 2025 AGI exceeded $150,000 (or $75,000 if married filing separately), you must pay 110% of your prior-year tax to use safe harbor, not 100%.

Safe harbor prevents the penalty -- not the underlying tax bill. If you owe $50,000 for 2026 but paid $30,000 in safe-harbor installments (based on a $30,000 prior-year tax liability), you will owe $20,000 when you file -- but no underpayment penalty.

How to pay:

The easiest method is the IRS Direct Pay tool at irs.gov/payments -- free, instant, no account required. You can also use EFTPS (IRS Electronic Federal Tax Payment System), which is better for recurring payments and lets you schedule ahead. Mailing a check with Form 1040-ES also works but is slower.

What if you miss a payment? The penalty is calculated based on how much you underpaid and for how long, at the current IRS interest rate (which changes quarterly). For 2026, it is roughly 7-8% annualized -- not catastrophic but worth avoiding.