Lands on Schedule SE — Self-employment tax — the part no withholding ever covered
If your employer withholds enough from a W-2 job to cover a small amount of side income, this article is not for you — the withholding may already be doing the work. It is not for the person who wants a single percentage to apply forever, either, because no honest one exists.
It is for someone paid on a 1099 who has searched some version of "how much tax will I owe" and found answers ranging from 15% to 40%, none of them showing their working.
The answer has two parts, and most confusion comes from knowing only the first. How much is a calculation. When is a schedule, and missing it costs money even when the total is right.
The short answer
| The question | The answer |
|---|---|
| Which taxes | Income tax and self-employment tax |
| Who withholds them | Nobody |
| $60,000 of profit, single, standard deduction | $12,037.20 — about 20% |
| When you must pay | Generally, if you will owe $1,000 or more |
| How often | Four instalments, unequal periods |
| The rule that makes a guess safe | Pay 100% of last year's tax |
How much: two taxes, not one
On a paycheck, two taxes come out before you see the money. On a 1099, both still apply and neither comes out.
Income tax is charged at your ordinary brackets on taxable income — the same 2026 brackets as a W-2, with the $16,100 standard deduction for a single filer taken first. Two deductions the self-employed get on top reduce it: half of self-employment tax, and the qualified business income deduction of up to 20%.
Self-employment tax is 15.3% on 92.35% of net profit, the Social Security and Medicare an employer would otherwise split with you.
Put through a real return — single, $60,000 of profit after expenses, no other income — the two come to $8,477.73 of self-employment tax and $3,559.47 of income tax: $12,037.20, just over 20% of profit. The full working, line by line, is in self-employed tax brackets.
Notice how far that is from the 25–30% figures that circulate. Those are not wrong for everyone: add a spouse's salary, a higher income, or state tax, and the number climbs. That is the case against a flat percentage, not for one. The self-employment tax calculator and the quarterly estimated tax calculator run the same arithmetic on your own figures.
When: four payments, and they are not quarters
The IRS generally expects estimated payments if you expect to owe $1,000 or more when you file. They are made with Form 1040-ES, for four periods of different lengths:
| Income earned | Payment due |
|---|---|
| 1 January – 31 March | April 15 |
| 1 April – 31 May | June 15 |
| 1 June – 31 August | September 15 |
| 1 September – 31 December | January 15, following year |
Two of those periods are not three months long, which is why "quarterly" misleads. The second covers two months; the fourth covers four. Income that arrives in April and May is due in June, not in July.
The schedule matters because the penalty is figured separately for each period. Paying the whole year's tax in April settles the bill but not the lateness: each earlier instalment that was due and not paid can still carry a penalty. The site's estimated taxes article works through why the timing beats the total, and every date for this filing season is on the deadlines page.
The safe harbour: how to pay without predicting the year
The hardest thing about 1099 income is that you do not know the year's total until it is over. The IRS rule on penalties answers that directly. You are generally protected if what you paid on time comes to at least the smaller of:
- 90% of this year's tax, or
- 100% of last year's tax — 110% if last year's adjusted gross income was over $150,000.
The second option needs no forecast. Last year's tax is a number already printed on last year's return. Divide it by four, pay it on the four dates, and the penalty question is settled for the year, however well or badly the year goes. If it goes well you will owe more in April — but a balance due in April is not a penalty.
A working method
- Work out one real year. Use last year's return, or run the calculators on this year's expected profit. You want a total, not a rate.
- Choose the safe harbour. For most people that is 100% of last year's tax (110% over $150,000 of AGI), split into four.
- Put the four dates in a calendar now. April 15, June 15, September 15, January 15.
- Move money on the day you are paid. A separate account holding a set share of each payment makes the instalments a transfer rather than a search.
- Recheck in September. If the year is far above last year's, a larger final payment narrows April's balance.
None of this changes what you owe. It changes whether the amount reaches the IRS on time, which is the only part of the bill that is optional.
Common questions
How much tax do I pay on 1099 income?
Should I set aside 25% or 30% of my 1099 income?
When are estimated tax payments due?
Do I have to pay estimated tax?
How do I avoid a penalty if my income is unpredictable?
Is paying the full amount in April enough?
This article is for educational purposes only and does not constitute tax, legal, or financial advice. Consult a qualified tax professional about your situation.