Guide · updated 2026-08-01
Quarterly taxes in your first year of self-employment
What changes when income arrives without withholding: self-employment tax on top of income tax, four payment dates that do not divide the year evenly, and the safe harbor that prevents a penalty when income is unpredictable.
Two taxes, not one
An employee splits Social Security and Medicare with their employer and never sees the employer half. Working for yourself, both halves become yours as self-employment tax: 12.4% for Social Security up to the annual wage base and 2.9% for Medicare with no cap, applied to 92.35% of net profit. That sits on top of ordinary income tax, which is why setting aside only an income-tax-sized amount is the classic first-year mistake.
The four dates are not quarters
Payments are due in April, June, September, and the following January. The periods they cover are three months, two months, three months, and four months — the calendar is not divided evenly, and the June payment arrives sooner than most people expect. Payments are made with Form 1040-ES or through the IRS's own payment portal.
The safe harbor is the number to aim at
You avoid an underpayment penalty by paying either 90% of the current year's tax — unknowable until the year ends — or 100% of last year's total tax, rising to 110% when prior-year adjusted gross income exceeded $150,000. The prior-year route is the usable one precisely because last year's figure is already known. Withholding from a spouse's job or your own part-time employment counts toward the total and is treated as paid evenly across the year.
Profit is not revenue
Self-employment tax applies to net profit after business expenses, and only once net earnings reach $400 for the year. Platform forms report gross settled payments before fees and commissions, which is why a 1099-K often shows more than reached your bank. Tracking expenses contemporaneously is what makes the difference defensible — mileage logs, receipts, and platform statements.
Set money aside on a schedule, not on instinct
Because the tax stack is not linear, a fixed percentage rule of thumb is wrong at most income levels — too little at the top, too much at the bottom. Running the calculation once and dividing gives a figure to move into a separate account each time you are paid, which is a more reliable habit than estimating at the deadline.
Official sources for this guide
Now do the math →
💸 Quarterly Estimated Tax Calculator 2026
Annual update alerts — new IRS and state figures the week they drop
One email when the numbers change. Double opt-in, no spam, unsubscribe anytime.