Quarterly Taxes for Small Business Owners
How your business structure changes your estimated taxes: S-corp payroll, partner K-1s, C-corp installments, and the safe harbor that keeps penalties off the table.
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What Are Estimated Taxes?
The U.S. tax system is "pay-as-you-go." W-2 employees have taxes withheld from every paycheck. Self-employed individuals and business owners must pay their own way, quarterly.
The $1,000 Rule
If you expect to owe $1,000 or more in federal taxes after subtracting withholding and refundable credits, the IRS requires you to make quarterly estimated payments.
Who Must Pay
Sole proprietors, single-member LLCs, S-Corp owners (on K-1 income), partners, freelancers, and anyone with significant non-wage income (investments, rental income, etc.).
This guide covers the small-business owner angle: how your entity type and payroll change the payments. For the full rules (the 90%, 100% and 110% targets and the zero-tax-last-year exception), see the estimated tax payments guide. Freelancers and online sellers have their own guide to quarterly taxes for online business owners, and sole proprietors can start with how much to set aside for 1099 taxes.
2026 Quarterly Tax Due Dates
Mark these dates. Missing them triggers automatic underpayment penalties.
| Quarter | Income Period | Payment Due |
|---|---|---|
| Q1 | Jan 1 to Mar 31 | April 15, 2026 |
| Q2 | Apr 1 to May 31 | June 15, 2026 |
| Q3 | Jun 1 to Aug 31 | September 15, 2026 |
| Q4 | Sep 1 to Dec 31 | January 15, 2027 |
* If a due date falls on a weekend or holiday, the deadline moves to the next business day. Use Form 1040-ES or pay online; see how to pay estimated taxes online.
As of October 2026, one 2026 installment is left: Q4, due January 15, 2027. Owners with payroll have a better tool than a January estimate: extra federal withholding on a December paycheck counts as paid evenly all year and can repair an earlier missed quarter. The Q4 estimated tax payment guide works the numbers.
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How to Calculate Your Payments
Two methods to calculate how much to pay each quarter, and one of them guarantees no penalties.
Safe Harbor Method
Pay 100% of last year's tax liability divided into 4 equal payments. If your AGI exceeded $150K, pay 110% of last year's liability.
The rule: meet the safe harbor and no underpayment penalty applies, even if you owe a large balance when you file. High earners should read the 110% rule.
Deep dive: the complete estimated tax payments guide, or check yourself with the penalty calculator.
Current Year Estimate
Estimate your current year's income, deductions, and credits, then pay 90% of the projected tax in quarterly installments. More precise but requires accurate forecasting.
Best for: Owners whose profit is falling from last year, so 90% of a current projection is lower than last year's number. Growing businesses usually do better with the safe harbor method.
The S-Corp Difference
If you run an S-Corp, your quarterly tax situation is different, and often simpler.
Payroll Withholding Covers Part of It
When you run payroll as an S-Corp owner, federal income tax, Social Security, and Medicare are withheld from each paycheck, just like a W-2 employee. This withholding counts toward your annual tax liability. If you're still sorting out how payroll and estimates fit together, our small business CPA services cover both.
You May Owe Less in Estimates
Because payroll withholding covers your salary income, you only need to make estimated payments on the distribution (K-1) portion of your income that isn't covered by withholding. This often dramatically reduces your quarterly payment amounts.
Estimates by Business Structure
The same safe harbor applies to every owner, but where the money comes from changes the best way to pay.
| Structure | What drives your personal estimate | Usual best way to pay |
|---|---|---|
| Sole proprietor or single-member LLC | Schedule C profit plus self-employment tax, no withholding | Quarterly 1040-ES payments, or a W-2 spouse raising withholding |
| S corporation owner | K-1 profit above your salary; salary is already withheld | Raise payroll withholding on your own salary; it counts evenly all year |
| Partner or multi-member LLC | Guaranteed payments plus your K-1 share, with no withholding | Quarterly payments; the annualized method helps when K-1 income is backloaded |
| C corporation owner | Salary and dividends only; the corporation pays its own tax | Personal withholding for salary; the corporation files its own installments |
Partners and S-corp owners often do not know their share of profit until the books close. That is where a mid-year projection, or the annualized income installment method, earns its keep. Selling the business, a building or equipment this year? See estimated tax on capital gains.
Underpayment Penalties
How they work, and how to make sure you never owe one.
How Penalties Work
The IRS calculates the penalty on Form 2210. They take each quarter's required payment, compare it to what you actually paid, and charge interest on the shortfall from the due date until you pay.
The current underpayment rate is the federal short-term rate plus 3 percentage points, updated quarterly. Even a small shortfall can result in hundreds in penalties over the year.
How to Avoid Them
- Pay 100% of prior year tax (110% if AGI > $150K)
- Or pay 90% of current year tax
- Make payments on time each quarter
- Use the annualized income method if income varies
- Increase W-2 withholding (if S-Corp or W-2 employed)
- Set up automatic IRS payments via EFTPS
Already received a penalty notice, or worried you will? Our estimated tax penalty guide walks through how the penalty is calculated and your options for reducing or removing it.
Let Us Handle Your Quarterly Taxes
With our monthly accounting service, we calculate your estimated payments, send you reminders before each deadline, and keep you on target as the year changes.
We Calculate
Quarterly estimates based on real-time financials, not last year's guess.
We Remind
Payment reminders 2 weeks before every due date so you're never late.
We Protect
Safe harbor targets calculated and tracked every quarter so you know where you stand before each due date.
Estimates are one piece of a bigger plan. Our small business tax planning strategies guide covers the moves that lower the number you owe, the year end tax planning for small business owners checklist covers the fourth-quarter deadlines, and a small business tax advisor can run all of it for you.
FAQs
Your questions about estimated tax payments, answered
What happens if I miss a quarterly payment?
The IRS charges an underpayment penalty at the federal short-term interest rate plus 3 percentage points, reset quarterly. For individuals it was 7% for most of 2026 (6% from April through June). The penalty runs on each missed or underpaid installment from its due date until you pay it or until the April 15 return due date, whichever comes first.
Do I need to pay quarterly taxes if I also have a W-2 job?
It depends. If your W-2 withholding covers your total tax liability (including self-employment income), you may not need to make estimated payments. Many business owners increase their W-2 withholding to avoid quarterly filings altogether. We can calculate the optimal approach for your situation.
Can I pay all my estimated taxes in one lump sum?
Technically yes, you can pay the full year's estimate with your Q1 payment in April. However, if your income varies significantly, you might overpay. The annualized income method allows you to pay based on actual income earned each quarter, which can reduce early-year payments.
How do state estimated taxes work?
Most states with income tax also require quarterly estimated payments, often on the same schedule as federal, but the percentages and safe harbors are set by each state. California, for example, uses a 30/40/0/30 split. Pass-through entity tax elections can also move the state payment from the owner to the business. We calculate and track both federal and state estimates for our monthly accounting clients.
What is the 'safe harbor' rule?
Safe harbor means your withholding and on-time estimated payments reach the smaller of 90% of this year's tax or 100% of last year's total tax (110% if last year's AGI exceeded $150,000). If you meet it, no underpayment penalty applies, even if you owe a large balance at filing time.
Does my C corporation make its own estimated payments?
Yes. A C corporation that expects to owe $500 or more pays its own estimated tax, figured on Form 1120-W. A calendar-year corporation's installments are due April 15, June 15, September 15 and December 15. Your personal estimates then cover only salary, dividends and other income that reaches your own return.
Want your quarterly taxes handled?
A free 30-minute call with our team about your needs, how we can help, and whether we are a good fit. Payment calculations, projections and tax advice come after engagement.
Tax planning slots are limited before year-end.
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Tax planning slots are limited before year-end.