Quarterly Tax Calculator (U.S. Federal)
Estimate your federal income and self-employment tax, then break it into four suggested 1040‑ES quarterly payments. Designed for freelancers, contractors, and small business owners.
Quarterly estimated tax calculator
How this quarterly tax calculator works
This tool estimates your U.S. federal income tax and self‑employment (SE) tax for the year, then divides the remaining balance into four suggested quarterly payments for Form 1040‑ES.
High‑level steps:
- Compute total income = W‑2 wages + self‑employment income + other taxable income.
- Subtract above‑the‑line deductions to get adjusted gross income (AGI).
- Subtract the larger of standard or itemized deductions to get taxable income.
- Apply the IRS tax brackets for your filing status to estimate income tax.
- Compute self‑employment tax on net SE income and allow the 50% SE tax deduction.
- Subtract non‑refundable credits.
- Subtract withholding and prior estimated payments.
- Divide the remaining balance by four to get suggested quarterly payments.
Self‑employment tax formula (simplified)
If you have freelance, contractor, or business income, you usually owe self‑employment tax for Social Security and Medicare.
We approximate SE tax as:
SE income subject to SE tax = 92.35% × net self‑employment
income
SE tax ≈ 15.3% × SE income subject to SE tax (up
to the Social Security wage base, with 2.9% Medicare above
that).
Half of the SE tax is treated as an above‑the‑line deduction when computing income tax.
Safe harbor rules (underpayment penalty basics)
The IRS generally won’t charge an underpayment penalty if you pay at least the safe harbor amount during the year, even if you end up owing more with your return.
- 90% of your current‑year total tax, or
- 100% of last year’s total tax (from Form 1040), or
- 110% of last year’s tax if your prior‑year AGI was over $150,000 (for most filers).
This calculator compares your projected total payments (withholding + estimates) to those safe harbor thresholds when you enter last year’s tax.
Quarterly due dates for estimated tax payments
For calendar‑year taxpayers, federal estimated tax payments are typically due on:
- 1st quarter: April 15
- 2nd quarter: June 15
- 3rd quarter: September 15
- 4th quarter: January 15 of the following year
If a due date falls on a weekend or federal holiday, the deadline moves to the next business day.
Limitations and assumptions
- Uses approximate IRS tax brackets and standard deductions for 2024–2025.
- Assumes all income is ordinary income (no special long‑term capital gains rates).
- Handles a single bucket of non‑refundable credits (no phase‑outs or complex rules).
- Does not calculate AMT, NIIT (3.8% net investment tax), QBI deduction, or state taxes.
For complex situations, large income swings, or major life changes, consider working with a tax professional or using full tax software.
FAQ
You generally need to pay quarterly estimated taxes if both of the following are true:
- You expect to owe at least $1,000 in tax for the year after subtracting withholding and refundable credits, and
- Your withholding and refundable credits will be less than 90% of your current‑year tax or 100% of your prior‑year tax (110% for some higher‑income taxpayers).
Self‑employed people, freelancers, landlords, and investors often fall into this group.
Yes. The IRS allows an annualized income method if your income is uneven during the year (for example, seasonal work). This calculator assumes even income and equal payments, which is simpler but may not be optimal if your income is highly variable.
No. This tool focuses on federal income and self‑employment tax. Many states have their own estimated tax rules and vouchers. Use this as a starting point and check your state’s revenue department for details.
No. This calculator is for education and planning only. It uses simplified assumptions and may not match your final tax return. For personalized advice, consult a qualified tax professional or CPA.