If you make Estimated Tax Payments, the fourth quarter is an important time to review where you stand.

Income can change considerably over the course of a year. Business owners may have a stronger or weaker year than expected. Independent contractors may add clients. Investors may realize capital gains. Retirees may receive additional taxable income. Any of these changes can mean the estimated tax amount calculated months ago no longer reflects your actual tax situation.

For calendar-year taxpayers, the fourth and final 2026 estimated tax payment is generally due January 15, 2027.

Instead of automatically sending the same amount you paid in previous quarters, Q4 gives you an opportunity to review your numbers and determine whether your final payment still makes sense.

1. Review Your Estimated Tax Payments Before Year-End

Estimated Tax Payments are intended to help taxpayers pay income tax throughout the year when enough tax isn’t being withheld from their income.

They are commonly associated with self-employed individuals and business owners, but estimated payments can also apply to taxpayers who receive investment income, rental income, retirement income, capital gains or other income that isn’t subject to sufficient withholding.

The IRS divides the year into four estimated-tax payment periods. For 2026, the fourth payment is generally due January 15, 2027.

You can review the IRS rules and current deadlines on its Estimated Taxes page.

2. Don’t Assume Your Q4 Payment Should Match the Previous Three

Many taxpayers calculate their Estimated Tax Payments early in the year and then make the same payment each quarter.

That can work when income remains relatively predictable.

But what if your financial situation changed?

Maybe your business had an unexpectedly strong second half of the year. Perhaps you picked up additional contract work, sold an investment, received a large bonus or experienced another source of taxable income.

The opposite can happen too. Business income may decline, an anticipated project may not happen, or deductible expenses may be significantly different than expected.

Your final estimated payment should be based on your current tax picture—not simply what you expected at the beginning of the year.

This is one reason accurate bookkeeping and business records become particularly valuable as year-end approaches. Reliable numbers make it much easier to evaluate whether your original tax estimate is still realistic.

3. Understand the Estimated Tax Underpayment Rules

The goal isn’t necessarily to predict your final tax bill down to the dollar.

The bigger concern is making sure enough tax has been paid throughout the year.

Generally, most taxpayers can avoid an estimated tax underpayment penalty if they owe less than $1,000 after subtracting withholding and refundable credits, or if they’ve paid at least:

• 90% of the tax owed for the current year, or
• 100% of the tax shown on the prior year’s return, whichever applicable amount is smaller.

Special rules apply in some situations, including certain higher-income taxpayers. For example, the prior-year percentage can increase to 110% when applicable income thresholds are exceeded.

The IRS provides additional details in Publication 505, Tax Withholding and Estimated Tax.

The rules can become more complicated when income isn’t earned evenly throughout the year, so don’t assume that simply catching up with a large January payment automatically eliminates a potential underpayment penalty.

4. Look at More Than Your Business Income

When reviewing Estimated Tax Payments, don’t look at one source of income in isolation.

Your overall tax situation may have changed because of income outside your primary business or job.

Consider whether you’ve experienced changes involving:

• Self-employment or contract income
• Investment income or capital gains
• Rental income
• Bonuses or commissions
• Retirement distributions
• A spouse’s income
• Major changes in deductions or credits
• Significant changes in withholding

If you also receive wages, adjusting paycheck withholding may sometimes be another way to address a potential shortfall.

This connects directly with our recent Tax Tip Tuesday discussion about using the Tax Withholding Estimator to determine whether federal income tax withholding is on track.

5. Don’t Wait Until January 14 to Review Your Numbers

The final 2026 estimated tax payment isn’t generally due until January 15, 2027, but that doesn’t mean January 14 is the best time to start calculating it.

Reviewing your situation during Q4 gives you time to gather records, update your bookkeeping, identify significant changes and determine whether your previous estimates are still reasonable.

It may also uncover issues that deserve attention before the calendar year closes.

If you’ve already made three Estimated Tax Payments, look at what you’ve paid so far and compare that amount with your updated income and projected tax liability.

If your income changed significantly during the year, determining the appropriate final payment may require more than simply dividing an annual estimate by four.

Who Should Pay Particular Attention to Estimated Tax Payments?

A Q4 review can be especially useful for business owners, sole proprietors, partners, S corporation shareholders, independent contractors and other taxpayers whose income isn’t fully covered by withholding.

It can also matter for people who experienced a significant financial event during the year.

If your income increased unexpectedly, waiting until you prepare your tax return to discover a substantial balance due can be an unpleasant surprise.

If your income decreased substantially, you may also want to determine whether continuing to make payments based on an outdated projection makes sense.

The important point is to work from current information rather than an estimate created months ago.

Estimated Tax Payments: The Bottom Line

The fourth estimated tax payment shouldn’t necessarily be an automatic repeat of the first three.

Q4 is an opportunity to review your income, deductions, credits, withholding and previous payments to determine whether your final Estimated Tax Payment is still appropriate.

For calendar-year individual taxpayers, the fourth 2026 estimated payment is generally due January 15, 2027.

Taking time to review your numbers before that deadline can help reduce the chance of an unexpected tax bill and may help you identify a potential underpayment issue while there is still time to address it.

At Cheshier Tax Resolution, we encourage taxpayers to stay informed about tax obligations throughout the year rather than waiting until filing season to discover a problem.

Frequently Asked Questions

When is the final 2026 estimated tax payment due?

For most calendar-year individual taxpayers, the fourth 2026 estimated tax payment is due January 15, 2027.

Who generally needs to make Estimated Tax Payments?

Estimated payments commonly apply to people who receive income that isn’t subject to sufficient withholding, including self-employment, business, investment, rental and certain retirement income.

Should all four Estimated Tax Payments be the same amount?

Not necessarily. Income and circumstances can change during the year. There are also special rules that may apply when income is earned unevenly. Your appropriate payment depends on your individual tax situation.

Can I make a larger final payment if my income increased?

Potentially. If your income increased during the year, reviewing your projected tax liability can help determine whether your final estimated payment should be adjusted. However, making a larger Q4 payment doesn’t necessarily eliminate penalties associated with earlier underpayments.

What happens if I don’t pay enough estimated tax?

You may owe an underpayment penalty, even if you ultimately receive a refund when you file. The calculation depends on how much tax was required, how much was paid and when those payments were made.

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