How to File Quarterly Estimated Taxes as a New Accounting Firm
Learn the step-by-step process for filing quarterly estimated taxes as a new accounting firm, including deadlines, calculation methods, and payment options.
Filing quarterly estimated taxes is a critical obligation for any new accounting firm operating as a sole proprietor, partnership, or S-corporation. If you expect to owe at least $1,000 in federal taxes for the year, the IRS requires you to pay estimated taxes quarterly. This guide walks you through the exact steps, deadlines, and methods to stay compliant and avoid penalties.
Understand Who Must Pay Estimated Taxes
You must pay quarterly estimated taxes if you are a sole proprietor, partner, or S-corporation shareholder and expect to owe $1,000 or more after subtracting withholding and credits. For C-corporations, the threshold is $500. Most new accounting firms fall into the first category, especially if you are the only owner or have no employees withholding taxes.
If you are an LLC taxed as a sole proprietorship or partnership, you pay estimated taxes on your personal return. If you elect S-corporation status, you must pay yourself a reasonable salary and withhold payroll taxes, but you still may need to pay estimated taxes on distributions and other income.
Calculate Your Estimated Tax Liability
To calculate your quarterly payments, you need to project your annual income, deductions, and credits. Use the IRS Form 1040-ES worksheet or your prior year’s tax return as a baseline. For a new firm, start with your expected net profit for the year, then subtract your standard deduction and any business expenses.
A common method is to pay 100% of your prior year’s tax liability (or 110% if your adjusted gross income was over $150,000) to avoid penalties. For example, if your 2025 tax liability was $12,000, you can pay $3,000 each quarter for 2026. If you are just starting and have no prior year, use the annualized income installment method, which requires you to calculate your income as of each quarter and pay based on that.
Use accounting software like QuickBooks or a tax calculator to estimate. Many CPAs recommend setting aside 25% to 30% of your net income for taxes, but your actual rate depends on your bracket and deductions.
Know the Quarterly Deadlines for 2026
Estimated tax payments are due four times a year. For the 2026 tax year, the deadlines are:
| Quarter | Payment Period | Due Date |
|---|---|---|
| Q1 | Jan 1 - Mar 31 | April 15, 2026 |
| Q2 | Apr 1 - May 31 | June 15, 2026 |
| Q3 | Jun 1 - Aug 31 | September 15, 2026 |
| Q4 | Sep 1 - Dec 31 | January 15, 2027 |
If a deadline falls on a weekend or holiday, the due date moves to the next business day. Mark these dates on your calendar and set reminders. Missing a deadline triggers a penalty, even if you pay the full amount later.
Choose Your Payment Method
The IRS offers several ways to pay your quarterly estimated taxes. The most convenient is the Electronic Federal Tax Payment System (EFTPS), which is free and allows you to schedule payments in advance. You can also pay online via IRS Direct Pay, by phone, or by mailing a check with Form 1040-ES voucher.
For state taxes, check your state’s revenue department website. Most states have similar quarterly schedules, but rates and thresholds vary. For example, California requires estimated payments if you expect to owe over $500, while Texas has no state income tax.
Use EFTPS to avoid mailing delays and get instant confirmation. Set up your account at least a week before the first deadline, as activation takes 5 to 7 business days.
Avoid Underpayment Penalties
The IRS charges a penalty if you underpay your estimated taxes, even by a small amount. The penalty is based on the current federal short-term rate plus 3 percentage points, compounded daily. For 2026, that rate is approximately 8% annually.
To avoid penalties, pay at least 90% of your current year’s tax liability or 100% of the prior year’s liability (110% if AGI over $150,000). If your income fluctuates, use the annualized income installment method to match payments to actual income. This requires filing Form 2210 with your tax return.
If you miss a payment, pay as soon as possible to minimize the penalty. The IRS calculates penalties from the due date to the payment date, so early payment reduces the cost.
Track Payments and Adjust Quarterly
Keep a ledger of all estimated tax payments, including date, amount, and method. This helps you reconcile at year-end and avoid double payments. Review your income and expenses each quarter and adjust your next payment if your projections change.
For example, if you land a large client in Q2, increase your Q3 payment to avoid a big balance due. Conversely, if income is lower than expected, reduce your payment but ensure you still meet the safe harbor threshold.
Use accounting software to run profit and loss statements quarterly. This gives you real-time data to make accurate estimates.
FAQ
What happens if I miss a quarterly deadline? You will owe a penalty calculated on the underpaid amount from the due date to the payment date. The penalty rate for 2026 is about 8% annually. Pay as soon as possible to reduce the penalty.
Can I pay estimated taxes with a credit card? Yes, the IRS allows credit card payments through third-party processors like PayUSAtax or Official Payments. They charge a convenience fee of around 1.87% to 2.5% of the payment amount. EFTPS is free and recommended.
Do I need to file a separate return for estimated taxes? No, estimated tax payments are not a tax return. You report them on your annual return (Form 1040 or 1120) and reconcile the total paid against your actual liability.
How do I handle state estimated taxes? Check your state’s department of revenue for specific forms and deadlines. Many states follow the federal schedule, but rates and thresholds differ. Some states, like New York, require estimated payments if you owe over $300.
The Bottom Line
Filing quarterly estimated taxes as a new accounting firm is straightforward if you plan ahead. Calculate your liability using the safe harbor method, mark the four deadlines, and pay via EFTPS to avoid penalties. Review your numbers each quarter and adjust as your income evolves. By staying on top of these payments, you avoid surprises at tax time and keep your firm in good standing with the IRS and your state. If you are unsure about your specific situation, consult a tax professional, but the steps above give you a solid foundation to start.