Quarterly Tax Calculator

Calculate how much you need to pay the IRS each quarter. Avoid underpayment penalties and stay on top of your tax obligations.

Enter Your Estimated 2026 Income

Your estimated total self-employment income for the year.

Include this for a more accurate marginal rate estimate.

Used for safe harbor calculations. Optional but recommended.

2026 Quarterly Deadlines

Q1 Payment
April 15, 2026
Jan 1 - Mar 31
Q2 Payment
June 16, 2026
Apr 1 - May 31
Q3 Payment
Sept 15, 2026
Jun 1 - Aug 31
Q4 Payment
Jan 15, 2027
Sep 1 - Dec 31

How to Use This Calculator

When I first started freelancing, I made the classic mistake: I waited until April to think about taxes. That year, I owed the IRS $6,400 in one lump sum, plus a small underpayment penalty because I hadn't paid quarterly. It was a painful lesson, but it taught me why quarterly estimated taxes exist and how to plan for them.

This calculator helps you avoid that same surprise. Here's how to use it step by step:

1. Estimate Your Annual 1099 Income

Look at how much you've earned so far this year and project the rest. If you're just starting out and have no idea, a conservative estimate is better than none. You can always adjust your payments in later quarters if your income changes. The IRS actually prefers this approach — they would rather you pay a little too much early on and scale back later than underpay and owe penalties.

2. Include Your W-2 Income

If you have a day job, add your expected W-2 salary. This matters because your side hustle income gets stacked on top of your W-2 income and is taxed at your highest marginal rate. For example, if your W-2 puts you in the 22% bracket, your freelance income will also be taxed at 22% federally (plus 15.3% self-employment tax). Without adding your W-2, the calculator might underestimate your total burden.

3. Subtract Business Expenses

You only pay quarterly taxes on your net profit, not your gross revenue. So if you expect to make $50,000 but spend $8,000 on software, equipment, and other business costs, your taxable base is $42,000. Keep a running list of expenses throughout the year so this number stays accurate.

4. Use the Safe Harbor Rule

Here's the good news: the IRS won't penalize you if you pay at least 100% of last year's total tax liability (or 110% if your income was over $150,000). Enter your total tax from last year's Form 1040, Line 24, and the calculator will show you the safe harbor amount. If your income jumped dramatically this year, paying the safe harbor amount protects you even if you end up owing more in April.

Pro tip from my own experience: I now set up a separate savings account nicknamed "Tax Jail" and transfer 25% of every client payment into it the same day. When a quarterly deadline rolls around, the money is already there. No scrambling, no stress.

5. Pay Online

The easiest way to pay is through IRS Direct Pay or the Electronic Federal Tax Payment System (EFTPS). Both are free. Make sure to select "Form 1040-ES" as the payment type so it gets credited correctly.

Common Questions

Who needs to pay quarterly estimated taxes?
Generally, you must pay quarterly if you expect to owe $1,000 or more in tax for the year and your withholding does not cover at least 90% of your current-year tax or 100% of last year's tax. Source: IRS Pub 505
What happens if I don't pay quarterly?
You may face an underpayment penalty, which is essentially interest on the amount you should have paid. The penalty is calculated based on how much you underpaid and for how long. For 2025, the IRS interest rate for underpayments is around 8% annually.
Can I pay unequal amounts each quarter?
Yes. You don't have to pay equal amounts. If your income is seasonal — for example, you earn more in Q4 — you can pay more in that quarter. This is called the annualized income installment method. You'll need to file Form 2210 with your tax return to show the IRS your income was uneven.
What is the safe harbor rule exactly?
The safe harbor protects you from penalties. If you pay at least 100% of last year's total tax (110% if your AGI was over $150,000), you won't owe an underpayment penalty even if you underpay for the current year. It's the easiest way to stay safe if your income is hard to predict.

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