Estimated Tax Payment Calculator
Calculate quarterly estimated tax payments to avoid IRS underpayment penalties.
Covers the safe harbor rule and projected tax owed based on annual income.
Quarterly estimated tax payments are required for self-employed individuals, freelancers, investors, and others who don’t have taxes automatically withheld from income. The IRS requires payments four times per year to avoid underpayment penalties.
Core formula: Estimated Annual Tax = Estimated Taxable Income × Effective Tax Rate Quarterly Payment = Estimated Annual Tax ÷ 4
Safe harbor rules (avoids underpayment penalty): Pay the lesser of:
- 100% of last year’s tax liability (110% if prior-year AGI exceeded $150,000)
- 90% of current year’s expected tax liability
Self-employment tax (on net self-employment income): SE Tax = Net SE Income × 0.9235 × 0.153 (15.3% = 12.4% SS + 2.9% Medicare) SE Tax Deduction = SE Tax × 0.5 (deductible on Schedule 1)
2025 IRS quarterly due dates:
| Quarter | Income Period | Due Date |
|---|---|---|
| Q1 | Jan 1 – Mar 31 | April 15 |
| Q2 | Apr 1 – May 31 | June 16 |
| Q3 | Jun 1 – Aug 31 | September 15 |
| Q4 | Sep 1 – Dec 31 | January 15 (following year) |
Worked example: Freelance designer expects $85,000 net income in 2025. Standard deduction: $15,000. Filing single.
Taxable income = $85,000 − $15,000 = $70,000 Estimated federal tax ≈ $10,294 (based on 2025 brackets) SE tax: $85,000 × 0.9235 × 0.153 = $12,006 SE deduction: $12,006 × 0.5 = $6,003 Adjusted taxable income: $70,000 − $6,003 = $63,997 Estimated total tax (federal + SE): ≈ $21,000/year Quarterly payment: $21,000 ÷ 4 = $5,250 per quarter
Pay via IRS Direct Pay (free) or EFTPS at irs.gov. State estimated taxes are separate and due on similar schedules — check your state revenue department.