How to File Quarterly Estimated Taxes as a New Architecture Firm
Learn the step-by-step process for paying quarterly estimated taxes as a new architecture firm, including deadlines, calculations, and penalty avoidance.
As a new architecture firm, you are likely operating as a sole proprietor, partnership, or S-corp, and the IRS expects you to pay taxes on your income throughout the year, not just at tax time. Quarterly estimated taxes are how you do that. This guide walks you through the exact steps to calculate, file, and pay them, so you avoid underpayment penalties and stay compliant.
Who Needs to Pay Quarterly Estimated Taxes?
You must pay quarterly estimated taxes if you expect to owe at least $1,000 in federal taxes for the year, after subtracting withholding and credits. As a new firm, you likely have no withholding, so you fall into this category. This applies to income tax, self-employment tax (Social Security and Medicare), and possibly alternative minimum tax.
If you are an S-corp, you may also need to make estimated payments for your personal income tax on wages and distributions, but the corporation itself may have different rules. Check with a CPA to confirm your specific structure.
Step 1: Estimate Your Annual Income and Taxes
Start by projecting your firm’s net income for the year. Use your business plan, current contracts, and expense projections. For a new firm, a conservative estimate is better than none. Here is a simple formula:
- Gross receipts: Total expected revenue from design fees, consulting, etc.
- Minus business expenses: Software (e.g., AutoCAD, Revit), office rent, marketing, insurance, professional fees, and any other ordinary and necessary costs.
- Equals net profit: This is what you pay self-employment tax on.
For 2026, the self-employment tax rate is 15.3% (12.4% for Social Security up to the wage base of $176,100, and 2.9% for Medicare with no cap). You also pay federal income tax based on your bracket, which ranges from 10% to 37%.
Example: If you project $80,000 net profit, your self-employment tax is $12,240, and your income tax might be around $8,000 (depending on deductions). Your total estimated tax for the year is roughly $20,240.
Step 2: Use the IRS Form 1040-ES Worksheet
Download IRS Form 1040-ES, which includes a worksheet to calculate your estimated tax. It walks you through adjusted gross income, deductions, credits, and total tax. You can also use the IRS Tax Withholding Estimator online, but for a business, the worksheet is more direct.
If you are unsure, use the safe harbor rule: pay at least 100% of the tax you owed last year (or 110% if your adjusted gross income was over $150,000). For a new firm with no prior year, this doesn’t apply, so you must estimate current year liability.
Step 3: Determine Your Payment Amount and Deadlines
Quarterly payments are due on these dates for the 2026 tax year:
| Quarter | Payment Due Date |
|---|---|
| Q1 (Jan-Mar) | April 15, 2026 |
| Q2 (Apr-May) | June 15, 2026 |
| Q3 (Jun-Aug) | September 15, 2026 |
| Q4 (Sep-Dec) | January 15, 2027 |
If a due date falls on a weekend or holiday, the deadline moves to the next business day. Each payment should be roughly 25% of your annual estimated tax, unless your income is uneven. If you have seasonal income, you can annualize your income using Form 2210 to pay lower amounts earlier in the year.
Step 4: Pay Your Estimated Taxes
You have several ways to pay. The easiest is IRS Direct Pay, which is free and allows you to pay directly from your bank account. You can also use the Electronic Federal Tax Payment System (EFTPS), which requires enrollment but is reliable for businesses. For credit card payments, the IRS uses third-party processors that charge fees (around 1.85% to 1.98%).
For state taxes, check your state’s revenue department. Most states have similar quarterly payment systems, often due on the same dates. For example, California requires estimated payments for LLCs and sole proprietors, with similar deadlines.
Payment methods compared:
| Method | Cost | Speed | Best For |
|---|---|---|---|
| IRS Direct Pay | Free | Instant | Most individuals |
| EFTPS | Free | Instant | Businesses with multiple payments |
| Credit card via processor | 1.85%-1.98% fee | Instant | Earning rewards |
| Check by mail | Postage cost | 1-2 weeks | Those who prefer paper |
Step 5: Track and Adjust Your Payments
Keep a ledger of your payments, including date, amount, and tax year. If your income changes significantly mid-year (e.g., you land a large contract), recalculate your estimated tax and adjust the next payment. You don’t need to file an amended form; just pay more or less in the next quarter.
If you overpay, you’ll get a refund when you file your annual return. If you underpay, you may owe interest and penalties, so it’s better to err on the side of paying slightly more, especially if you’re uncertain.
Avoid Underpayment Penalties
The IRS charges a penalty if you underpay your estimated taxes by more than $1,000, unless you meet the safe harbor rule. The penalty is based on the federal short-term interest rate plus 3%, and it accrues daily. To avoid this, pay at least 90% of your current year tax liability, or 100% of last year’s liability (110% if AGI over $150,000). For a new firm, aim for 90% of your projected liability.
Common Mistakes to Avoid
- Forgetting state taxes: Many states require estimated payments, and penalties can be steep.
- Ignoring self-employment tax: It’s easy to focus on income tax, but SE tax is a big chunk.
- Not accounting for deductions: Use all eligible business deductions (home office, equipment, professional development) to lower your taxable income.
- Missing deadlines: Set calendar reminders at least a week in advance.
FAQ
Q: What if I miss a quarterly deadline? A: Pay as soon as possible. The penalty is calculated from the due date, so paying late is better than not paying at all. You can also request a penalty waiver if it’s your first time and you have reasonable cause.
Q: Can I pay estimated taxes from my business account? A: Yes, but for sole proprietors, it’s often cleaner to pay from a personal account since it’s your personal tax liability. For S-corps, the corporation may need to make payments separately.
Q: Do I need to file a separate form for quarterly payments? A: No, you just send payment with Form 1040-ES voucher (if paying by mail) or electronically. You don’t file a separate tax return until year-end.
Q: What if my income is irregular? A: Use the annualized income installment method on Form 2210. This lets you pay based on when you actually earn income, which can reduce penalties if you earn more later in the year.
The Bottom Line
Quarterly estimated taxes are a non-negotiable part of running a new architecture firm. By estimating your income, using Form 1040-ES, paying on time via IRS Direct Pay, and adjusting as your business grows, you’ll avoid penalties and stay on the IRS’s good side. Set up a system now: calculate your first payment, mark the deadlines on your calendar, and set aside a percentage of every invoice into a separate tax savings account. A CPA who works with small businesses can help you refine your estimates and ensure you’re not overpaying. Take action this week to get your first payment scheduled.