Quarterly Estimated Tax Calculator
Estimate what to send the IRS each quarter so you are not blindsided in April — federal SE + income tax, plus an optional state line.
Your details
Rough figures are fine — you can refine later.
How we calculate this
We annualize your full-year federal tax with the shared freelancer engine, add an optional state estimate, and divide by four. All rates and caps come from our versioned tax-constants.json.
1. Annual federal tax. freelancerFederalTax = self-employment tax + federal income tax on taxable income (net profit − half of SE tax − standard deduction − QBI).
2. State tax. Net profit × the flat state rate you enter (optional).
3. Per quarter. (Federal + state) ÷ 4.
4. Safe harbor. The lesser of 90% of this year’s tax or 100%/110% of the prior-year tax you enter (110% approximated when net profit exceeds $150k). Meeting it avoids the underpayment penalty.
Assumptions: sole proprietor on Schedule C, standard deduction, even quarterly payments. Uneven earners should consider the annualized-installment method.
Primary sources
- IRS Form 1040-ES, Estimated Tax for Individuals
- IRS Publication 505, Tax Withholding and Estimated Tax
- IRS Form 2210 (underpayment / annualized-installment method)
Why freelancers pay taxes four times a year
When you're on a W-2, your employer withholds tax from every paycheck and sends it to the IRS for you. As a freelancer, nobody does that. The IRS still wants its money throughout the year, though — so it asks the self-employed to pay estimated taxes in four installments. Skip them and you can owe an underpayment penalty on top of the tax itself, even if you pay in full come April.
This calculator estimates your full-year federal tax (self-employment tax plus income tax), adds an optional state estimate, and splits the total into four quarterly payments so you know what to send and when.
The four due dates
Federal estimated payments are generally due April 15, June 15, September 15, and January 15 of the following year. The periods aren't even calendar quarters — the first covers three months, the next two, then three, then four — but the equal-payment approach this tool uses is what most freelancers do and is perfectly acceptable. The January payment settles the final stretch of the prior year.
If a due date falls on a weekend or federal holiday, it rolls to the next business day.
The safe harbor: your penalty shield
Here's the rule that saves freelancers from nasty surprises. You avoid the underpayment penalty if you pay at least the safe-harbor amount — the *lesser* of:
- 90% of this year's tax, or
- 100% of last year's tax (or 110% if your prior-year AGI was over $150,000).
The second option is powerful: if you had a big year coming and paid 100%/110% of last year's smaller bill in even installments, you're protected from penalties no matter how much more you earn — you just settle the difference at filing. That's why this tool shows a safe-harbor minimum alongside the full estimate.
How to use the result
- Automate it. Set a calendar reminder for each due date and pay online through IRS Direct Pay or EFTPS.
- Set money aside as you earn. Don't wait until the due date to find the cash. Park a percentage of every payment in a separate account.
- Recalculate mid-year. Freelance income is lumpy. If your outlook changes, rerun the numbers and adjust the remaining payments.
- Don't forget state. If your state has an income tax, it usually wants estimated payments too, often on a similar schedule.
What this assumes
This is a planning estimate for a sole proprietor on Schedule C taking the standard deduction, paying in four equal installments. If most of your income arrives late in the year, look into the annualized-installment method (Form 2210, Schedule AI), which matches payments to when you actually earn.
Estimates only — not tax advice. Confirm your specific situation and state obligations with a qualified professional.
Common questions
When are quarterly estimated taxes due? + −
Federal estimated payments are generally due April 15, June 15, September 15, and January 15 of the following year. If a date lands on a weekend or holiday it shifts to the next business day. The January payment covers the final quarter of the prior year.
What is the safe harbor rule? + −
You avoid the underpayment penalty if you pay at least 90% of the current year’s tax, or 100% of last year’s tax (110% if your prior-year AGI was over $150,000) — whichever is smaller. Paying the safe-harbor amount protects you even if you end up earning more than you expected.
What if my income is uneven through the year? + −
You can use the annualized-installment method (IRS Form 2210, Schedule AI) to match payments to when you actually earn the income, rather than paying equal quarters. This helps if most of your income arrives late in the year.
Do I pay state estimated taxes too? + −
If your state has an income tax, usually yes, and often on a similar schedule. This tool includes an optional flat state estimate; check your state’s own rules and forms for the exact amount and due dates.
Keep going
Prepared for tax year 2026. Every rate and cap on this page cites a primary IRS or SSA source. Estimates only — not tax or financial advice. — for planning purposes only, not tax, legal, or financial advice.