Estimated Quarterly Tax Calculator
Calculate IRS Form 1040-ES quarterly estimated tax installments, safe harbor thresholds (100% / 110% rules), and statutory payment deadlines.
Safe Harbor Quarterly Schedule
IRS Safe Harbor & Quarterly Payment Formula
Safe Harbor Target = min(Current Year Tax × 90%, Prior Year Tax × (AGI > $150k ? 110% : 100%)) | Net Quarterly Due = (Safe Harbor Target − W-2 Withholding) ÷ 4- IRS Safe Harbor Rules: You avoid underpayment penalties if you pay at least 90% of your current year tax liability OR 100% of your prior year tax liability (110% if prior year AGI exceeded $150,000).
- Four Annual Deadlines: Q1 (April 15), Q2 (June 15), Q3 (September 15), Q4 (January 15 of following year).
Step-by-Step Worked Example
Calculation Steps:
How to Use This Calculator
Assumptions & Limitations
- Payments must be remitted on or before statutory IRS due dates to avoid failure-to-pay interest.
Frequently Asked Questions
Who must pay estimated quarterly taxes?
Anyone who expects to owe at least $1,000 in federal tax for the year after subtracting federal withholding and refundable credits, including freelancers, independent contractors, business owners, landlords, and investors.
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