Frequently Asked Questions
How the quarterly tax calculator works and what to know about estimated taxes.
About Quarterly Estimated Taxes
Who needs to pay quarterly estimated taxes?
Generally, you must pay quarterly estimated taxes if you expect to owe at least $1,000 in federal tax for the year after subtracting withholding and refundable credits. This commonly affects freelancers, consultants, independent contractors, and sole proprietors receiving 1099 income.
What are the 2026 quarterly payment due dates for tax year 2025?
For 2025 income the IRS due dates are: Q1 — April 15, 2026; Q2 — June 15, 2026; Q3 — September 15, 2026; Q4 — January 15, 2027. Dates can shift when they fall on weekends or holidays. Always confirm at irs.gov.
What is self-employment (SE) tax?
Self-employment tax covers Social Security (12.4%) and Medicare (2.9%) taxes. When you're an employee, your employer pays half; when self-employed, you pay both halves. The SE tax is calculated on 92.35% of your net profit (the 0.9235 multiplier approximates the employee share). You can deduct 50% of SE tax paid from your gross income when computing AGI.
What is the 2025 Social Security wage base?
For 2025, the Social Security wage base is $168,600. Income above this threshold is not subject to the 12.4% SS portion of SE tax, though Medicare (2.9%) still applies to all earnings.
What is "Net Self-Employment Profit"?
This is your Schedule C net profit — total freelance / 1099 revenue minus allowable business expenses (software, equipment, home office, etc.). It is not your gross revenue. If you have multiple Schedule C businesses, enter the combined net total.
About This Calculator
What does this calculator include?
This tool models: 2025 federal income tax brackets (Single, MFJ, Head of Household), the standard deduction for each filing status, self-employment tax (Social Security + Medicare), the 50% SE tax deduction, and above-the-line deductions for traditional 401(k)/IRA and HSA contributions.
What does this calculator NOT include?
State income taxes, tax credits (child tax credit, earned income credit, etc.), itemized deductions, Alternative Minimum Tax (AMT), the 0.9% Additional Medicare Tax on high earners, net investment income tax, QBI deduction for pass-through income, or any special-situation phase-outs. This is intentionally simplified for a general estimate.
Are my calculations saved anywhere?
No. All calculations run entirely in your browser. No data is collected, transmitted, or stored. See our Privacy Policy for details.
How accurate is this estimate?
This tool provides a reasonable starting estimate for planning purposes. Because it excludes credits, itemized deductions, and special situations, your actual tax liability may be lower (or in unusual cases higher). Always verify with a tax professional or the IRS withholding estimator before making payment decisions.
I have both W-2 income and 1099 income. Can I use this?
Yes. Enter your W-2 wages in the optional "Other W-2 Wages" field and your federal withholding in the "Federal Withholding Expected" field. The calculator will combine both income sources, apply SE tax only to the 1099 portion, and account for your withholding when computing the estimated amount due.
Payments & Penalties
What happens if I underpay?
The IRS charges an underpayment penalty if you owe more than $1,000 at filing and did not pay enough through withholding or estimated payments during the year. The safe harbor rule generally protects you if you pay 100% of last year's tax liability (or 110% if your prior-year AGI exceeded $150,000), or 90% of your current year's actual liability.
How do I actually make the payments?
The easiest method is IRS Direct Pay at irs.gov/payments/direct-pay. You can also use the Electronic Federal Tax Payment System (EFTPS), pay by debit/credit card, or mail Form 1040-ES with a check.
Can I pay more than the quarterly amount to be safe?
Yes. Paying more than estimated never results in a penalty. Any overpayment will be credited toward your tax balance at filing time, and you can choose to receive it as a refund or apply it to next year's estimated taxes.
This FAQ is for general informational purposes only and does not constitute tax or legal advice. Tax rules can change. Consult a qualified tax professional for guidance specific to your situation.