Quarterly Estimated Tax Calculator
Work out quarterly estimated tax payments for 2026 and the safe-harbor amount that avoids IRS penalties.
About the Quarterly Estimated Tax Calculator
If you'll owe $1,000 or more after withholding, you generally must pay estimated tax in four instalments. You avoid the underpayment penalty by paying at least 90% of this year's tax or 100% of last year's (110% if last year's AGI was over $150,000).
The formula
Required = min(90% × 2026 tax, 100% or 110% × 2025 tax) − withholding
Worked example
Example: Pay each quarter = $2,475
- Inputs: Filing status: Single; Expected 2026 self-employment profit: $66,000; Other taxable income: $0; Tax withheld from wages: $0; Your total 2025 tax (Form 1040 line 24): $9,900; Your 2025 AGI: $72,000.
- Formula: Required = min(90% × 2026 tax, 100% or 110% × 2025 tax) − withholding
- Result: Pay each quarter = $2,475
Things to keep in mind
- Uses the standard deduction and ignores credits; check Form 1040-ES.
Questions people ask
Can I pay online?
Yes, through IRS Direct Pay or your IRS online account.
What happens if I pay too little estimated tax?
The IRS can charge an underpayment penalty, worked out like interest on the amount short for each quarter. Paying at least 100% of last year's tax (110% if your AGI was over $150,000), spread over the four due dates, avoids it.