Quarterly Tax Estimates: A Small Business Guide

Quarterly estimated taxes are pay-as-you-go federal tax payments that self-employed individuals, sole proprietors, partners, and S corporation shareholders must make four times a year when they expect to owe at least $1,000 in federal tax after subtracting withholding and refundable credits. Corporations use a lower threshold of $500. This guide is current as of 2026 and covers the 2026 tax year unless otherwise noted.

Key Takeaways

• Individuals who expect to owe $1,000 or more in federal tax (after withholding and credits) must generally make quarterly estimated payments; the threshold for corporations is $500 (IRS).
• For the 2026 tax year, federal estimated tax payments are due April 15, June 15, September 15, and January 15, 2027 (TaxAct).
• The federal safe harbor rule lets you avoid underpayment penalties by paying at least 90% of your current-year tax or 100% of your prior-year tax, whichever is less — rising to 110% if your prior-year AGI exceeded $150,000 (IRS).
• For tax year 2026, the Social Security wage base for self-employment tax increases to $184,500 (IRS Publication 334).
• You can adjust later quarterly payments if your income changes mid-year — you are not locked into your first estimate (TaxAct).

Who Is Required to Pay Estimated Taxes?

According to the IRS, individuals — including sole proprietors, partners, and S corporation shareholders — generally must make estimated tax payments if they expect to owe tax of $1,000 or more when their return is filed. Corporations generally must make estimated payments if they expect to owe $500 or more.

This commonly affects:

• Self-employed individuals and freelancers
• Sole proprietors filing Schedule C
• Partners in a partnership
• LLC owners (depending on how the LLC is taxed)
• S corporation shareholders who receive pass-through income not covered by withholding

W-2 employees whose employers withhold enough tax to cover at least 90% of their liability generally have no quarterly estimated tax requirement. However, a W-2 employee who also earns significant self-employment or investment income may still need to make estimated payments on that additional income.

One exception worth noting: self-employed individuals must pay self-employment tax on net earnings of $400 or more, and that self-employment tax is factored into their quarterly estimated tax calculations (Paychex).

If you did not owe any tax in the prior year, you are generally not required to make estimated payments for the current year (IRS).

When Are Quarterly Estimated Taxes Due in 2026?

For the 2026 tax year, the federal estimated tax payment deadlines are as follows (TaxAct; IRS FAQ):

If a due date falls on a weekend or legal holiday, the deadline moves to the next business day (TaxAct).

One shortcut for Q4: You can skip the January 15 payment if you file your annual return and pay all tax due by February 1 (TurboTax FAQ).

Note that the income periods are unequal — Q2 covers only two months (April–May) while Q4 covers four months (September–December). This is a quirk of the IRS schedule, not an error. Plan your cash accordingly.

How Do I Calculate My Estimated Taxes?

Calculating your quarterly estimated tax involves estimating your full-year income and tax liability, then dividing by four. Here is the step-by-step process (hiline.co; TurboTax):

1. Estimate your expected annual gross income — total revenue before deductions.
2. Calculate your Adjusted Gross Income (AGI) by subtracting eligible business deductions.
3. Estimate your income tax by applying the applicable tax rate to your AGI.
4. Calculate self-employment tax on your net self-employment earnings.
5. Add income tax and self-employment tax to get your estimated annual tax liability.
6. Divide by four to determine each quarterly payment.

The IRS Form 1040-ES includes a worksheet that walks through this calculation. Your prior-year tax return is a useful starting point for estimating the current year.

Self-Employment Tax: Wage Base by Tax Year

Self-employment tax covers Social Security and Medicare. The Social Security portion applies only up to an annual wage base that adjusts each year. Per IRS Publication 334:

• For tax year 2025, the maximum net self-employment earnings subject to the Social Security portion of self-employment tax is $176,100. There is no maximum limit on earnings subject to the Medicare portion.
• For tax year 2026, that Social Security wage base increases to $184,500. There is again no cap on the Medicare portion.

High earners — individuals with earned income of $200,000 or more, or married couples filing jointly with income of $250,000 or more — are subject to an additional 0.9% Medicare tax (TurboTax).

Hypothetical Calculation Example

The following is a hypothetical illustration only — not a benchmark or observed outcome.

Consider a hypothetical sole proprietor with $100,000 in annual gross revenue and $30,000 in business deductions. Their taxable income would be $70,000 (hypothetical). They would then estimate income tax on that $70,000 and add self-employment tax on their net self-employment earnings to arrive at a total estimated annual tax. Dividing that total by four gives each quarterly payment amount. The IRS Form 1040-ES worksheet handles this calculation in full.

What Are the Safe Harbor Rules?

The safe harbor rules let you avoid an underpayment penalty even if you end up owing more tax than you paid during the year. Per the IRS and confirmed by TaxAct, you generally avoid the penalty if your withholding and timely estimated payments equal at least:

• 90% of your current-year tax liability, or
• 100% of your prior-year tax liability (whichever is smaller)

Higher-income exception: If your prior-year AGI exceeded $150,000 (or $75,000 if married filing separately), the prior-year safe harbor threshold increases to 110% of last year's tax liability (TurboTax; TaxAct).

Hypothetical Safe Harbor Example

The following is a hypothetical illustration only.

Suppose a hypothetical business owner paid $20,000 in total federal tax last year and their prior-year AGI was under $150,000. Under the prior-year safe harbor, paying $5,000 per quarter ($20,000 ÷ 4) would protect them from underpayment penalties — even if their income rises significantly this year (Paychex).

The safe harbor approach is particularly useful for service businesses with variable income. If you had a strong prior year, basing payments on that amount gives you a predictable, penalty-free floor while you assess the current year's trajectory.

What If My Income Changes During the Year?

You are not locked into your first quarterly estimate. If your income increases or decreases mid-year, you can adjust later payments (TaxAct). The key is to keep your bookkeeping current each quarter so your estimates stay accurate.

If you start earning taxable income partway through the year: You do not owe back payments for earlier quarters you missed. Your first payment is due on the next installment date after you begin earning income. However, you may need to pay a larger percentage to catch up. For example, if you first become liable in Q3, your September 15 payment would cover 75% of the estimated annual tax due (TurboTax FAQ). Use IRS Form 2210 to show the IRS that your payments align with when income was actually received — otherwise the IRS assumes income was earned evenly throughout the year.

If your income is uneven: The IRS allows you to annualize your income and make unequal estimated payments that match your actual income pattern. This is done using the Annualized Estimated Tax Worksheet in IRS Publication 505 and attaching Form 2210 to your return (IRS FAQ).

For service businesses — agencies, consultancies, and studios where revenue can spike in certain quarters — this annualization method can prevent overpaying early in the year when cash is tighter. See our guide on tax planning for marketing agencies with contractor-heavy teams for more on managing variable income.

What Forms Do I Need to Pay Estimated Taxes?

The form you use depends on your business structure (US Chamber of Commerce):

How to pay (TaxAct; IRS):

• IRS Direct Pay — free, online, no registration required
• EFTPS (Electronic Federal Tax Payment System) — required for corporations; available to all; provides a payment history you can reference
• IRS2Go app — mobile payment option
• Mail — send a Form 1040-ES voucher with a check

The IRS recommends EFTPS for businesses because it provides a searchable payment history, which is useful when reconciling what you've paid against what you owe at year-end.

What Happens If I Miss a Quarterly Payment?

Missing or underpaying a quarterly estimated tax payment can trigger an underpayment penalty — even if you expect a refund when you file your annual return (IRS).

Per Paychex, penalties start at 0.5% of the total amount due and begin accruing as soon as you miss the deadline. The penalty increases each month the payment remains unpaid, up to a maximum of 25%.

If you miss a deadline: Make the payment as soon as possible. The penalty accrues on the unpaid amount for each day it remains outstanding, so earlier is always better (US Chamber of Commerce).

Penalty waivers may be available in limited circumstances (hiline.co; US Chamber of Commerce):

• You were a victim of a natural disaster or incapacitating accident
• You retired after turning age 62 during the tax year
• You became disabled during the current or prior tax year
• There was reasonable cause for the underpayment

Consult a tax professional before assuming a waiver applies to your situation. For more on how extensions and payment deadlines interact, see our guide on tax extension vs. payment deadline.

How Should I Track What I've Paid?

Accurate tracking of estimated tax payments prevents surprises at year-end and ensures you can claim credit for every payment on your annual return. Report all estimated tax payments on Form 1040, line 26, including any overpayment from a prior year that you elected to apply as a credit (IRS FAQ).

Practical tracking steps:

1. Use EFTPS — it maintains a searchable payment history by date and amount.
2. Record each payment in your accounting system on the date it is made, not the due date.
3. Reconcile quarterly — before each payment, compare your year-to-date books against your estimated annual liability to confirm you are on track.
4. Keep payment confirmations — save confirmation numbers or bank records for every payment.

Clean, current books are the foundation of accurate estimates. If your books are closed late or inconsistently, your quarterly estimates will be based on stale data — which leads to either overpaying (a cash flow drag) or underpaying (a penalty). A predictable monthly close makes this process significantly more reliable. Our month-end close calendar template shows exactly how to structure that cadence.

The Qualified Business Income (QBI) Deduction

Service business owners should factor the QBI deduction into their estimated tax calculations. As of 2026, recent legislation has made the 20% QBI deduction permanent for qualified active trades or businesses (IRS Publication 334; IRS Publication 505).

Beginning in 2026, if you have a minimum of $1,000 in total qualified business income from an active trade or business, you may be able to claim a minimum QBID of $400 (IRS Publication 505).

For tax year 2025, the QBI deduction begins to phase out for single filers with taxable income above $197,300 and joint filers above $394,600. For tax year 2024, those limits were $191,950 and $383,900 respectively (TurboTax).

The QBI deduction can meaningfully reduce your estimated tax liability. If you are eligible, factor it into your Form 1040-ES calculation rather than discovering it only at year-end.

Frequently Asked Questions

Who is required to pay estimated taxes?

Individuals — including sole proprietors, partners, and S corporation shareholders — must generally make estimated tax payments if they expect to owe $1,000 or more in federal tax after subtracting withholding and refundable credits. Corporations use a $500 threshold. W-2 employees with sufficient withholding are generally exempt. (IRS)

What are the 2026 quarterly estimated tax due dates?

For the 2026 tax year, federal estimated tax payments are due April 15 (Q1), June 15 (Q2), September 15 (Q3), and January 15, 2027 (Q4). If a due date falls on a weekend or legal holiday, it shifts to the next business day. (TaxAct)

Do I still have to make estimated payments if I don't earn income until later in the year?

No — you owe estimated payments only for the quarters in which you have taxable income. If you first become liable in Q3, your first payment is due September 15. You may need to use IRS Form 2210 to show the IRS that payments align with when income was actually received. (TurboTax FAQ)

Can I use my prior-year tax refund to pay estimated taxes?

Yes. Any overpayment from your prior-year return that you elect to apply as a credit — rather than receive as a refund — counts toward your current-year estimated tax payments. Report all estimated tax payments, including applied credits, on Form 1040, line 26. (IRS FAQ)

Disclaimer: Laya provides this content for informational purposes only. This material does not constitute tax, legal, or accounting advice. Tax rules change frequently; confirm all thresholds and deadlines with an official IRS source or your own tax advisor before acting. Please consult your own tax, legal, and accounting advisors before engaging in any transaction.

If quarterly estimates feel like a moving target because your books aren't current, that's the underlying problem to fix. Book an intro call to see how a predictable monthly close keeps your estimates accurate and your tax surprises to a minimum.