Estimate the quarterly estimated tax you owe on 1099 and self-employment income, split into self-employment tax, federal tax and state tax.
| Net SE Income | Self-Employment Tax | Federal Income Tax | State Tax | Per Quarter |
|---|---|---|---|---|
| $80,000 net / 15.3% SE / 18% fed / 5% state | $12,240 | $14,400 | $4,000 | $7,660 |
| $150,000 net / 15.3% SE / 22% fed / 6% state | $22,950 | $33,000 | $9,000 | $16,238 |
| $50,000 net / 15.3% SE / 12% fed / 0% state | $7,650 | $6,000 | $0 | $3,412 |
| $250,000 net / 15.3% SE / 24% fed / 6% state | $38,250 | $60,000 | $15,000 | $28,312 |
Each row uses the same arithmetic the calculator runs: the 15.3% self-employment tax (12.4% Social Security + 2.9% Medicare on 92.35% of net profit), your marginal federal rate on net profit, and your state rate — then divides the annual total into four equal quarterly payments. Safe-harbor figures are shown separately because the IRS lets you pay 100% of last year’s tax (110% if AGI over $150,000) to avoid underpayment penalties.
| Payment | Income period covered | Due date |
|---|---|---|
| Q1 | Jan 1 – Mar 31 | April 15 |
| Q2 | Apr 1 – May 31 | June 15 |
| Q3 | Jun 1 – Aug 31 | September 15 |
| Q4 | Sep 1 – Dec 31 | January 15 (next year) |
The periods are uneven — the IRS quarters are not calendar quarters. If a due date falls on a weekend or holiday, the deadline rolls to the next business day. Pay online through IRS Direct Pay or EFTPS; most states have an equivalent portal.
When you are a W-2 employee, your employer withholds tax from every paycheck and sends it to the IRS. When you earn self-employment income reported on a 1099-NEC or 1099-K, nobody withholds for you. The US tax system is pay-as-you-go, so the IRS expects four estimated payments across the year rather than one lump sum in April. Miss them and you can owe an underpayment penalty even if you pay every dollar by the filing deadline.
You avoid the underpayment penalty if you pay at least 90% of this year’s tax, or 100% of last year’s tax (110% if your prior-year AGI exceeded $150,000). The prior-year harbor is the easier target when income is climbing, because it is a fixed number you already know. Paying the prior-year amount in four equal installments is the standard tactic for freelancers whose income is volatile.
If you discover a shortfall mid-year, the fix is to increase the remaining payments rather than panic. The penalty is computed per quarter on the amount you should have paid, so catching up early reduces it. You can also ask your employer to withhold extra from a W-2 job using Form W-4 — withholding is treated as paid evenly across the year, which can retroactively cure an early-year shortfall.
⚠️ Important: This calculator applies flat rate estimates to net profit and is not a substitute for a full tax return. Actual liability depends on deductions, credits, the Social Security wage base ($176,100 in 2025), the Additional Medicare Tax above $200,000, and your state’s specific rules. Confirm with a tax professional.