| Direct Answer: The June estimated tax checkpoint is a critical mid-year moment for small business owners to review year-to-date income, compare projected annual earnings against prior-year tax liability, and determine whether current estimated payments are on pace — or dangerously underfunded. If your business has grown, you had a strong first half, or your income mix has shifted, adjusting your estimates now is almost always the right move. The IRS imposes underpayment penalties when quarterly payments fall short of safe harbor thresholds, and a proactive mid-year review with a trusted advisor can prevent a painful surprise when you file. |
Most business owners treat estimated taxes as a box to check — send in a payment four times a year and move on. But that approach assumes your income this year will look exactly like it did last year. If your business is growing, or if the first half of the year has brought in more revenue than you expected, that assumption may already be costing you.
The quarterly payment due in mid-June is not just a routine deadline. It is a checkpoint — an opportunity to pause, look at what the year is actually shaping up to be, and make sure your tax payments are keeping pace. Get this right, and you move into the second half of the year with clarity and cash flow confidence. Get it wrong, and you could owe a penalty before you even finish calculating your return.
Business owners do not have an employer withholding income tax from every paycheck. Instead, the IRS expects you to pay as you go through four quarterly estimated tax installments. These payments cover your federal income tax, self-employment tax, and — depending on how your business is structured — any tax on S-Corp distributions or pass-through income.
When those payments fall short, the IRS charges an underpayment penalty. This is not a penalty for bad behavior — it is simply a built-in charge for the time value of money. And it accrues from the date the payment was due, not from the filing deadline. That means you can owe a penalty even if you pay everything in full by April.
According to IRS data, underpayment penalties affect millions of taxpayers each year, including many business owners who simply did not adjust as their income changed. For the firm's clients — particularly S-Corp shareholder-employees managing a combination of salary and distributions — the stakes are even more nuanced, because owner compensation decisions interact directly with estimated tax obligations. A trusted advisor who understands your full picture is essential to getting this right.
The IRS provides a legal escape hatch called the safe harbor rule. If your estimated payments meet certain thresholds, you avoid the underpayment penalty regardless of how much you owe when you file.
There are two safe harbor options to understand:
The AICPA and major tax publishers including Thomson Reuters Checkpoint and Wolters Kluwer all flag the prior-year safe harbor as the more straightforward protection for most business owners — particularly in strong growth years. But knowing which option applies and whether your current payments are on track requires running actual numbers, not guessing.
The mid-year checkpoint is not complicated, but it does require intentional attention. Here is a practical framework for what to assess:
Pull your profit and loss report through the end of May or the most recent period available. Look at gross revenue, cost of goods sold or direct costs, and operating expenses. Calculate your net income. This is your actual starting point — not an estimate, not a budget, but what happened.
If you do not have clean, up-to-date books, this step alone becomes a problem. Decision-ready financial records are not just a compliance necessity — they are the foundation of proactive planning. Without them, you are making tax decisions based on incomplete information.
Take your year-to-date net income and project it forward. For most service businesses, a simple annualization — multiplying your first-half results by two — is a reasonable starting point. If your business is seasonal or has a large contract closing later in the year, adjust accordingly.
Now compare that projected annual income to your prior-year income. If it is materially higher, the prior-year safe harbor may give you more breathing room. If it is lower, the current-year 90% safe harbor may be the better path. Either way, you need both numbers to choose the right strategy.
Add up all estimated payments you have made so far this year, plus any withholding from a W-2 position if applicable. Compare that total to 100% (or 110%) of your prior-year tax liability. If you are short, calculate the gap.
Remember that estimated payments are made in four installments, but the installments are not evenly spaced. The January 15 payment covers the fourth quarter of the prior year. The April 15 and June 15 payments come quickly together. September 15 and the following January cover the back half of the year. Understanding where you are in that cycle matters for how you distribute any catch-up payments.
For S-Corp owners, estimated taxes are only part of the picture. Your salary level directly affects payroll taxes, and distributions are not subject to self-employment tax — but they are also not a substitute for a reasonable salary in the eyes of the IRS. If your business is having a strong year, now is also the time to revisit whether your officer salary is appropriately calibrated.
The IRS has consistently scrutinized S-Corp owner compensation, and the Bradford Tax Institute has documented numerous cases where the IRS reallocated distributions as wages when officer salaries were deemed unreasonably low. Getting this right mid-year, rather than at filing time, is significantly easier and less expensive.
The June checkpoint is also an opportunity to ask what planning moves are still available for the year. Have you maximized retirement plan contributions? Do you have a Section 179 or bonus depreciation purchase planned? Have you evaluated whether an accountable plan is in place to reimburse home office, mileage, or other business expenses?
These decisions do not have to wait until December. In fact, acting earlier in the year gives you more flexibility and better outcomes. This is exactly the kind of proactive, integrated analysis that separates a trusted advisor relationship from a once-a-year tax preparation transaction.
| Fictional Example: The following story is a fictional, illustrative example only. It is not based on any real client or actual situation. It is provided to show how Business Advisory and Accounting Partners would approach estimated tax planning for a business owner in a growth year. |
Jordan owns a physical therapy practice in Nashville, Tennessee. The practice has grown steadily over the past several years, and the first quarter brought in significantly more revenue than the same period last year — driven by a new referral relationship with a nearby orthopedic group.
Jordan had been paying estimated taxes based on last year's liability, which felt like a reasonable approach. But by May, it was clear the practice was on pace to generate meaningfully more income than the prior year. The problem was that Jordan had not adjusted the payments.
When Jordan sat down with our advisory team before the June deadline, the picture became clear quickly. Using Jordan's year-to-date financials, the team projected annual net income and identified that the prior-year safe harbor threshold had not yet been met through the first three payments. A catch-up calculation showed how much additional payment was needed by June 15 to achieve safe harbor protection for the full year.
Beyond the immediate payment question, our team would also advise Jordan to review officer salary. The practice's profitability had increased significantly, which meant that the existing W-2 salary might no longer represent reasonable compensation given current earnings — a flag that could attract IRS scrutiny. Adjusting salary now, rather than waiting until year-end, would allow payroll to reflect the updated compensation rate across the remaining pay periods.
Finally, our team would identify two additional planning opportunities: an increase to Jordan's SEP-IRA contribution limit based on the higher projected income, and a planned equipment purchase before year-end that could be expensed under Section 179, reducing taxable income materially.
Jordan left the meeting with a clear action plan: a specific additional estimated payment to make before June 15, a revised officer salary to implement, and two additional year-end moves to plan for. None of that would have happened if the June checkpoint had been treated as just another quarterly payment date.
If you see pieces of your own business in this hypothetical example, it may be time to sit down with a Business Advisory and Accounting Partners advisor and talk through your numbers.
Business Advisory and Accounting Partners powered by Harness was built around a simple but important distinction: any CPA firm can record history. Our advisory firm helps you build a future. Estimated tax planning is a perfect illustration of that difference.
A compliance-focused preparer will calculate what you owe after the year is over and tell you the number. A trusted advisory partner reviews your trajectory mid-year, identifies the gap before it becomes a penalty, and connects your tax obligations to your broader compensation, retirement, and cash flow strategy.
The firm has been providing advisory services since 2014 and tax and accounting guidance since 1989. With the additional scale and resources that come from being powered by Harness, our advisory team works with clients across the country to build planning rhythms — not just filing relationships. For business owners managing the complexity of growth, that rhythm is what turns tax season from a source of stress into a strategic milestone.
An advisory fit meeting is not a tax preparation appointment. It is a structured conversation about where your business is, where it is headed, and what planning decisions will have the most impact over the next twelve months.
In that conversation, we typically review your current financial position, discuss your estimated tax status and whether adjustments are needed, and identify any open planning questions — compensation, retirement, deductions, entity structure — that deserve attention before year-end.
You walk away with a clear view of your current tax trajectory, a short list of priority actions, and a realistic sense of whether ongoing advisory support makes sense for your situation. There is no obligation to move forward beyond the meeting.
These conversations are most valuable for business owners who are growing, who have had a materially different year than expected, or who have simply never had a proactive mid-year tax conversation with someone who understands their full picture.
If you want to make sure your estimated tax payments are on track — and identify every planning opportunity still available this year — schedule a conversation with our advisory team. We work with business owners across the country to turn quarterly checkpoints into genuine planning opportunities.
Schedule your advisory fit meeting at busadvisory.com
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Yes — if your income has increased materially over the prior year, your current estimated payments may no longer be sufficient to meet safe harbor requirements. The IRS requires that you either pay 100% of last year's total tax liability (110% if prior-year AGI exceeded $150,000) or 90% of the current year's actual liability, whichever applies to your strategy. A mid-year review of your year-to-date financials is the most reliable way to determine whether your payments are on pace and what adjustment, if any, is needed before the next quarterly deadline.
The safe harbor rule is an IRS provision that protects you from underpayment penalties even if you owe additional tax when you file. There are two thresholds: pay 100% of your prior-year tax liability (or 110% if your prior-year adjusted gross income exceeded $150,000), or pay 90% of your current-year liability through estimated payments and withholding. For most growing businesses, the prior-year safe harbor is the more straightforward target, because it does not require a precise current-year projection. However, the right strategy depends on your specific situation, which is why working through the numbers with an advisor before each quarterly deadline is worth the effort.
If your estimated payments fall below the IRS thresholds, you will be assessed an underpayment penalty — even if you pay everything owed by the filing deadline. The penalty is calculated based on the federal short-term interest rate plus three percentage points, and it accrues from the date each quarterly payment was due. As Thomson Reuters Checkpoint and other tax research platforms have documented, this penalty cannot simply be avoided by paying a lump sum in April; it is calculated quarter by quarter throughout the year. Catching and correcting a shortfall at the June checkpoint is significantly less costly than discovering it at filing.
Start with your projected annual net income, then estimate your total federal income tax liability using the applicable tax brackets. For self-employed individuals, add self-employment tax on net earnings. For S-Corp owners, your calculation will be based on your taxable income — which includes your W-2 salary — rather than distributions, though distributions factor into your overall financial planning. Divide the projected annual liability by four for a rough baseline, then compare that total to the prior-year safe harbor threshold to determine which method results in lower required payments. An advisory firm that understands your entity structure and compensation strategy will be able to build a more precise projection.
A review tied to each quarterly deadline — April, June, September, and January — is the minimum. For businesses with significant income variability, a mid-quarter check can also be worthwhile, especially after a large contract closes or a major expense occurs. According to AICPA guidance on proactive tax planning, business owners who review their tax position at least quarterly are significantly less likely to face underpayment penalties or year-end surprises. The June checkpoint is particularly important because it falls shortly after first-half results are available and before the second half of the year is locked in.
Withholding is income tax taken directly from wages before you receive a paycheck — most commonly from a W-2 salary. Estimated taxes are payments you make directly to the IRS to cover tax on income that is not subject to withholding, such as business profits, self-employment income, or investment gains. For S-Corp owners who pay themselves a salary, the withholding on that salary counts toward your annual estimated payment requirement. One often-overlooked strategy: if you are behind on estimated payments mid-year, increasing withholding on your W-2 salary through year-end can help close the gap, because withholding is treated as paid evenly throughout the year for purposes of the underpayment penalty calculation.
The best time is before each quarterly deadline — especially the June installment, which serves as a natural mid-year checkpoint after actual first-half results are available. If your income has changed materially from the prior year, if you have made significant business investments, or if you are facing a growth event such as a major new client, a new hire, or a real estate transaction, talking with an advisor before making your payment is particularly valuable. Business Advisory and Accounting Partners works with business owners year-round — not just at tax time — to make sure estimated payments are accurate, safe harbor thresholds are met, and every available planning move has been identified. You can schedule a conversation at busadvisory.com/schedule-your-advisory-fit-meeting/.
You cannot reverse a payment once it is submitted, but you can adjust future quarterly payments based on updated projections. If you overpaid in one quarter, the excess is credited against your next installment or refunded when you file. If you underpaid, you can make a larger payment in a subsequent quarter to reduce the penalty, though the penalty for the missed quarter may still apply. This is why a forward-looking advisory approach — building projections at each checkpoint rather than reacting after the fact — is far more efficient than trying to correct course after a payment is made.
Most small businesses operate on a calendar year, and the standard estimated tax deadlines — April 15, June 15, September 15, and January 15 — apply to them. Fiscal-year businesses follow a different schedule, with deadlines tied to the 15th day of the fourth, sixth, ninth, and twelfth months of their fiscal year. If your business operates on a fiscal year, the specific deadlines and safe harbor calculations work differently, and working through them with an advisor who understands your filing structure is important to avoid errors.
A traditional tax preparer calculates what you owe and files your return. Business Advisory and Accounting Partners powered by Harness builds a proactive planning rhythm around your business — reviewing your estimated tax position at every quarterly checkpoint, connecting those payments to your compensation strategy, retirement contributions, and year-end planning opportunities, and flagging issues before they become penalties. Our advisory team has been working with business owners since 2014, with tax and accounting expertise dating to 1989. We do not just record history — we help our clients build a financially stronger future, one planning conversation at a time.
