Income and self-employment tax payments the self-employed send the IRS four times a year, since no employer withholds tax from their pay.
Quarterly estimated taxes are the payments the self-employed send the IRS four times a year, because no employer is withholding tax from their checks. They cover both income tax and self-employment tax, and the deadlines fall in April, June, September, and January.
For sellers, this is the number-one first-year surprise: you owe tax as you earn, not just on April 15. Miss the quarterly payments and you can face underpayment penalties even if you pay in full later. A common rule of thumb is to set aside 25–30% of every payment, though your rate depends on your income and state. For buyers, this doesn’t affect you directly, but it’s why many freelancers price to account for taxes they pay themselves.
The safest approach is a separate savings account you feed from each invoice, so the money’s there when payments come due. Our guide on freelance taxes basics walks through the mechanics — and because penalties and safe-harbor rules are specific, confirm your amounts with a tax professional.