Why you owe quarterly taxes
The U.S. tax system is "pay as you go." Employees satisfy it through paycheck withholding, but when you're self-employed, no one withholds tax for you — so the IRS expects four estimated payments across the year. Skip them and you can owe an underpayment penalty even if you pay your full balance in April. This calculator turns your expected profit into a quarterly payment that covers both your self-employment tax and your federal income tax.
How to use it
- Enter your expected annual net profit — your self-employment income after business expenses.
- If you also have a W-2 job, add those wages and any federal tax already withheld, which reduces what you need to pay in estimates.
The result is your suggested per-quarter payment, plus a breakdown of the self-employment and income tax behind it and the four 2026 due dates.
The safe-harbor rule
You don't have to predict your tax perfectly. You avoid the underpayment penalty if your timely payments cover the smaller of 90% of this year's tax or 100% of last year's tax (110% if your prior-year AGI was over $150,000). Paying based on last year's return is the easy, penalty-proof route when your income is rising.
The 2026 due dates
| Quarter | Income period | Due date |
|---|---|---|
| Q1 | Jan 1 – Mar 31 | April 15, 2026 |
| Q2 | Apr 1 – May 31 | June 15, 2026 |
| Q3 | Jun 1 – Aug 31 | September 15, 2026 |
| Q4 | Sep 1 – Dec 31 | January 15, 2027 |
Pay online with IRS Direct Pay (free, from a bank account) or EFTPS. The "quarters" are uneven — note Q2 is only two months — so mark the dates rather than assuming an even three-month spacing.
If your income is uneven
Seasonal or lumpy income? The standard "divide by four" approach can over-charge you early in the year. The IRS annualized income installment method lets you pay each quarter based on what you actually earned in that period. It's more paperwork, but it can lower or eliminate a penalty for uneven earners. Full detail is in our estimated taxes guide, and you can see your take-home after these payments with the 1099 take-home calculator.