Estimated Quarterly Tax Calculator
Self-employed or have side income? Estimate your quarterly tax payment — income tax plus the 15.3% self-employment tax.
Self-employed tax and bookkeeping tools
Learn moreTwo taxes, four payments
The self-employed owe two federal taxes: regular income tax and self-employment tax (15.3% for Social Security and Medicare, since you pay both halves). The IRS wants it in four quarterly installments — underpay and you can owe a penalty.
How it’s calculated & sources
Self-employment tax = 92.35% of profit × 15.3%. Taxable income = profit − half the SE tax − the standard deduction; income tax applies the brackets. Total − withholding, divided by four, is each quarterly payment. State tax is not included.
Source: IRS self-employment tax (15.3%) and 2025 brackets. Safe harbor: pay 100% (110% if high income) of last year’s tax to avoid penalties.
Results update as you type and are general estimates, not personalized financial, tax, medical or legal advice. Verify with a professional.
Worked example
On $80,000 of self-employment profit (single), SE tax is about $11,300 and income tax about $9,200 — roughly $20,500 total, or about $5,100 per quarter.
Frequently asked questions
When are the payments due?
Generally April 15, June 15, September 15 and January 15. Mark them — missing them risks an underpayment penalty.
How do I avoid a penalty?
Use the safe harbor: pay at least 100% of last year’s total tax (110% if your income is high), even if this year ends up higher.