Quarterly Estimated Tax Calculator (US)
For the self-employed and 1099 contractors: calculate self-employment tax, income tax, and the quarterly payment that meets the IRS safe harbor to avoid an underpayment penalty.
Self-employment net profit, Schedule C
Determines the 100% vs 110% safe-harbor rate
Quarterly Due Dates
| Quarter | Due Date | Amount |
|---|---|---|
| Q1 | April 15 | $3,500.00 |
| Q2 | June 15 | $3,500.00 |
| Q3 | September 15 | $3,500.00 |
| Q4 | January 15 (following year) | $3,500.00 |
A worked example
On an expected net profit of $90,000, self-employment tax comes to $12,716.60, plus income tax of $9,571.17 — a total estimated liability of $22,287.77.
With a prior-year liability of $14,000, the safe harbor requires paying at least $14,000.00 over the year — split into four quarterly payments of $3,500.00 each.
Frequently asked questions
Who needs to pay quarterly estimated taxes?
Generally, anyone who expects to owe $1,000 or more in federal tax for the year and doesn't have enough withheld through an employer — most commonly the self-employed, freelancers, and 1099 contractors, but also investors with large capital gains or other untaxed income.
What is self-employment tax?
Self-employment (SE) tax is the self-employed equivalent of Social Security and Medicare (FICA) tax — 15.3% combined (12.4% Social Security up to the wage base, plus 2.9% Medicare) on 92.35% of net profit. As a W-2 employee, your employer would normally pay half of this for you.
What is the IRS safe harbor for estimated taxes?
You generally avoid an underpayment penalty if you pay at least 90% of this year's tax liability, or 100% of last year's liability (110% if your prior-year AGI was over $150,000) — whichever is smaller. This calculator computes both and uses the lower, easier-to-hit target.
When are quarterly estimated taxes due?
Despite the name, the four 'quarters' are not equal calendar quarters: payments are typically due April 15, June 15, September 15, and January 15 of the following year. Dates shift slightly if they fall on a weekend or holiday.
Can I deduct half of my self-employment tax?
Yes — the IRS lets you deduct the employer-equivalent half of your SE tax from your gross income when calculating income tax, which this calculator applies automatically.