Fourth Quarter Estimated Tax Payment: Due January 15, 2027, and How to Avoid the Penalty

If you're self-employed, freelance, or have income with no tax withheld, the last estimated tax payment for 2026 is due Friday, January 15, 2027. It's the one people forget, because it lands just after the holidays and belongs to the year that just ended. Here are the dates, the safe harbor rules that decide whether you owe a penalty, and a checklist to work through in December.

The four 2026 due dates

Estimated tax for the 2026 tax year is paid in four instalments (Form 1040-ES):

• Q1: April 15, 2026
• Q2: June 15, 2026
• Q3: September 15, 2026
• Q4: January 15, 2027

When a due date falls on a weekend or federal holiday, it moves to the next business day. January 15, 2027 is a Friday, so no shift is expected. These dates match what the major tax-preparation sites list, but check Form 1040-ES on IRS.gov before you pay.

The safe harbor rules: how much is enough?

You generally avoid an underpayment penalty if your payments and withholding for the year add up to the smaller of:

• 90% of this year's tax, or
• 100% of last year's tax, or 110% if last year's adjusted gross income was over $150,000 ($75,000 if married filing separately).

The second option is useful when income jumps mid-year: pay based on last year's bill and you're protected, even if the final number is bigger. Withholding from a job or retirement account counts as paid evenly through the year, so it can reduce what you need in Q4.

Can I skip the Q4 payment?

IRS guidance says you don't have to make the January payment if you file your 2026 return and pay the full balance by January 31, 2027. That can be handy, but only if you can really file that early. Many people wait for forms that arrive late in January, so paying by the 15th is the safer plan.

A December checklist

• Early December: add up income so far and compare it with what you've paid in.
• Mid December: estimate the year's tax, or use last year's return for the safe harbor number.
• Before the holidays: schedule the payment online or through your tax account so it isn't waiting on January.
• January 15: pay, and save the confirmation.
• After paying: set a reminder for Q1 2027, usually April 15.

Frequently asked questions

When is the Q4 2026 estimated tax payment due? January 15, 2027.

Is the fourth quarter payment for 2026 or 2027? It's the last payment for the 2026 tax year, even though you pay it in January.

What if I miss a payment? The IRS can charge an underpayment penalty for the period the money was late. Paying as soon as you notice limits it.

Do I need to pay estimated tax if I only have a job? Usually not. If your employer withholds enough, you can skip them. Self-employment, rental, investment and side income are the usual triggers.

This is general information, not tax advice. A tax professional can check your numbers.

How ReminderIt helps

Tax deadlines are easy to miss because nothing rings when they arrive. ReminderIt calls your phone at the time you choose and sends a WhatsApp message with Done and Snooze buttons.

Message ReminderIt on WhatsApp something like "Remind me on December 14 to work out my Q4 estimated tax" and "Remind me on January 12 to pay my estimated tax". There's a 7-day free trial with no card, then it's $7/month.