Quarterly Estimated Tax Calculator
Example: Expected annual business income: 90000 $ · Business deductions & adjustments: 15000 $ · Effective income tax rate: 15 %
| Quarterly payment | $5,462 |
| Total estimated annual tax | $21,847 |
| Self-employment tax | $10,597 |
| Income tax | $11,250 |
Worked example
Expect $90,000 of business income with $15,000 of deductions, leaving $75,000 taxable. Self-employment tax on 92.35% of that at 15.3% is about $10,597, and income tax at a 15% effective rate is $11,250, for a total near $21,847. Divided by four, each quarterly estimated payment is about $5,462. Setting that aside every quarter is how you avoid both a big April bill and an underpayment penalty.
Frequently asked questions
When are quarterly taxes due?
Federal estimated taxes are generally due in four installments, around mid-April, mid-June, mid-September, and mid-January of the following year. Mark the dates, since missing them triggers penalties even if you pay in full later.
How do I avoid an underpayment penalty?
Generally you must pay at least 90% of the current year's tax or 100% of last year's (110% for higher incomes) through withholding and estimates. Paying evenly across the quarters keeps you in the safe harbor.
What effective tax rate should I use?
Use a blended rate that reflects your federal bracket after deductions, and add state tax separately if it applies. This tool handles self-employment tax on its own, so the rate you enter is for income tax only.
Does this include state taxes?
No. It estimates federal income tax plus self-employment tax. If your state has an income tax, calculate and set aside that amount separately, as many states also require quarterly estimates.