If you're self-employed, a freelancer, or earn significant 1099 income, the IRS expects you to pay taxes as you earn — not just once a year. Missing that isn't just inconvenient; it can mean an underpayment penalty on top of the tax itself.
Who actually needs to pay quarterly
As a general rule, if you expect to owe $1,000 or more in tax for the year after subtracting withholding and credits, you're expected to make estimated payments. This typically covers freelancers, independent contractors, small business owners, and anyone with significant investment or rental income that isn't already covered by employer withholding.
The four deadlines
Despite the name, the four "quarters" aren't evenly spaced. The typical schedule is:
- Q1: April 15 — covers income from January through March.
- Q2: June 15 — covers April and May (just two months).
- Q3: September 15 — covers June through August.
- Q4: January 15 of the following year — covers September through December.
Dates shift slightly if they fall on a weekend or holiday. Set calendar reminders a week ahead of each one; the penalty for missing a payment accrues from the due date, not from when you eventually notice.
How to estimate what you owe
The simplest starting point is your prior year's tax return. The IRS offers two "safe harbor" thresholds that protect you from underpayment penalties even if your estimate turns out to be low:
- Pay at least 90% of your current year's actual tax liability, or
- Pay at least 100% of last year's total tax (110% if your prior-year adjusted gross income was above $150,000).
Whichever of those two numbers is smaller is your safe target. If your income is fairly steady year to year, the 100%/110% prior-year rule is usually the easier one to calculate and hit.
Don't forget self-employment tax: on top of income tax, self-employed earners owe roughly 15.3% in Social Security and Medicare taxes on net earnings, which W-2 employees split with their employer. This is often the piece that catches new freelancers off guard.
A simple quarterly checklist
- Total your net self-employment income so far this year.
- Apply your effective tax rate from last year's return as a rough estimate, or use IRS Form 1040-ES worksheets for a more precise number.
- Add self-employment tax (~15.3% of net earnings, with an income cap that adjusts annually).
- Subtract any tax already withheld from other income (a spouse's W-2, for example).
- Divide the remaining estimated liability across the remaining payment periods.
- Pay via IRS Direct Pay, EFTPS, or your state's equivalent — and keep the confirmation.
If you missed a prior deadline: pay as soon as possible rather than waiting for the next one. The underpayment penalty is calculated based on how late and how much was underpaid — waiting only adds up.
State estimated taxes
Most states with an income tax run a parallel estimated payment system with similar (though not always identical) deadlines. Check your state revenue department's site directly, since state safe harbor thresholds and due dates can differ from the federal ones.
This is general information, not personalized tax advice — a CPA or enrolled agent can fine-tune your specific numbers, especially if your income is irregular or you had a major life change this year.