Quarterly Estimated Tax Calculator
Calculate how much to pay each quarter in estimated taxes to avoid IRS underpayment penalties. Designed for freelancers, self-employed workers, and anyone with income not covered by employer withholding.
Last updated: May 2026
About this calculator
The IRS requires you to prepay taxes throughout the year if you expect to owe at least $1,000. The safe harbor rule lets you avoid penalties by paying the lesser of 100% of last year's tax liability (110% if prior-year income exceeded $150,000) or 90% of the current year's estimated liability. This calculator uses: annualTax = max((expectedIncome − deductions) × marginalRate, priorYearTax × safeHarborMultiplier). Your quarterly payment = max(0, annualTax − withholdingCredits) ÷ 4. The marginal rate is 22% for single filers and 24% for married filers. IRS due dates for quarterly payments are typically April 15, June 15, September 15, and January 15.
How to use
Suppose you are single, expect $80,000 income, $10,000 in deductions, had $14,000 in prior-year tax, expect $2,000 in withholding, and earned under $150,000 last year. Current-year estimate = ($80,000 − $10,000) × 0.22 = $15,400. Safe harbor = $14,000 × 1.0 = $14,000. Annual tax basis = max($15,400, $14,000) = $15,400. Net after withholding = $15,400 − $2,000 = $13,400. Quarterly payment = $13,400 ÷ 4 = $3,350 per quarter.
Frequently asked questions
How do I know if I need to make quarterly estimated tax payments?
You generally need to make estimated payments if you expect to owe at least $1,000 in federal taxes after subtracting withholding and credits, and your withholding will cover less than 90% of this year's tax or 100% of last year's tax. This most commonly applies to freelancers, independent contractors, small business owners, landlords, and investors with significant capital gains. Employees with a side hustle can sometimes avoid quarterly payments by increasing their W-4 withholding at their primary job instead. Use the IRS Form 1040-ES worksheet to confirm your obligation.
What is the IRS safe harbor rule for estimated taxes?
The safe harbor rule protects you from underpayment penalties if you pay at least 100% of your prior year's total tax liability in estimated payments and withholding combined — or 110% if your prior-year adjusted gross income exceeded $150,000. Even if you end up owing more at filing time, no penalty applies as long as the safe harbor threshold was met. This makes prior-year tax a useful planning anchor when your current-year income is unpredictable. You can find your prior-year total tax on line 24 of your most recent Form 1040.
What happens if I miss a quarterly estimated tax payment deadline?
Missing a quarterly due date triggers an IRS underpayment penalty calculated using the federal short-term interest rate plus 3 percentage points, applied to the underpaid amount for the number of days it was late. Unlike a late-filing penalty, the underpayment penalty is assessed per quarter, so catching up in a later quarter does not erase the penalty for the earlier missed period. The penalty is typically modest but can add up if you skip multiple quarters. You can request a penalty waiver on Form 2210 if you had unusual circumstances such as a casualty, disaster, or inconsistent income stream.