No Withholding Means You're on the Hook Yourself
When you work as a 1099 freelancer or independent contractor, the business paying you generally doesn't withhold any income tax โ that's the opposite of a W-2 job. Instead, you're expected to send the IRS quarterly estimated tax payments throughout the year covering both income tax and self-employment tax (Social Security and Medicare, 15.3% combined). If your total payments fall short of the IRS's safe harbor โ usually 90% of your current year's tax bill โ you can be hit with an underpayment penalty on top of the tax you still owe. The penalty works like interest, accruing on the shortfall for each quarter you underpaid. Freelancers with multiple income streams or a big year-over-year income jump are especially likely to get caught off guard, so checking your estimated payments against your actual tax liability partway through the year can help you avoid a surprise bill โ and a penalty โ the following April.
How It's Calculated
| Step | Item | Formula |
|---|---|---|
| 1 | Net SE Income | 1099 Income ร (1 โ Expense Rate) |
| 2 | Self-Employment Tax | Net Income ร 92.35% ร 15.3% |
| 3 | Total Tax | Federal Income Tax (progressive) + SE Tax |
| 4 | Penalty | max(0, 90% of Total Tax โ Payments Made) ร ~8% |
Frequently Asked Questions
Businesses generally don't withhold income tax from 1099 payments. Freelancers must pay estimated taxes quarterly throughout the year instead.
The IRS generally won't penalize you if you paid at least 90% of your current year's tax, or 100-110% of last year's tax.
It's an interest-like charge on the shortfall each quarter, based on the federal short-term rate plus 3%. This tool gives a simplified full-year estimate.
โป This is a simplified full-year estimate using 2025 single-filer federal brackets and does not replicate the IRS's exact quarterly Form 2210 calculation or state taxes.