Four dates, four checks to the IRS. How to estimate, what the safe-harbor rule is, and how to avoid the surprise April bill forever.
When you're a W-2 employee, taxes get withheld from every paycheck. The IRS gets paid in real time as you earn. When you're self-employed, no one withholds anything — so the IRS asks you to send four checks per year instead.
This isn't optional. If you'll owe more than $1,000 in federal tax for the year and you don't make quarterly payments, the IRS charges an "underpayment penalty" — usually 6–8% of the underpaid amount, calculated as if it were interest you owed on a loan. Annoying and avoidable.
The good news: as long as you make four reasonable payments, you're fine. The IRS doesn't require perfect estimation — they want regularity.
For 2026, the federal quarterly deadlines are: Q1 (Jan–Mar income) due April 15. Q2 (Apr–May income) due June 15. Q3 (Jun–Aug income) due September 15. Q4 (Sep–Dec income) due January 15, 2027.
Yes, the "quarters" are weird — Q2 covers two months and Q4 covers four. Don't fight it. Just put the four dates on your calendar.
Most states with income tax have parallel deadlines on the same dates. Check your state tax agency's website — they typically have a form similar to federal Form 1040-ES.
Two methods. Method one (simple): take your prior year's total tax bill, divide by 4, send that amount each quarter. This is the "safe harbor" rule — pay 100% of last year's tax (110% if you made over $150,000) and the IRS cannot charge an underpayment penalty no matter what you actually end up owing.
Method two (real): each quarter, calculate your year-to-date net profit, project it for the full year, calculate your estimated tax (federal income + self-employment + state), divide by 4, send a quarter of it. This is more accurate but requires actual math each quarter.
Most freelancers should use the safe harbor method. It's simpler, it's mathematically guaranteed to avoid penalties, and any over- or under-payment gets reconciled at year-end. Method two only beats safe harbor in years when your income drops significantly — in which case you're overpaying with safe harbor and would want to pay less.
Federal: the easiest way is IRS Direct Pay (irs.gov/payments). Free, takes 2 minutes, works directly from your bank account. Schedule the payment for the due date and you're done. You can also use EFTPS (the IRS's payment system, requires enrollment) or mail a check with Form 1040-ES.
State: every state with income tax has its own portal — search "[your state] estimated tax payment." Most accept ACH debit similar to IRS Direct Pay.
Pro move: open a separate "tax savings" bank account, set up an automatic transfer of 25–30% of every business deposit into it, then pay quarterly taxes from that account. The money is never "yours to spend" because it never feels like yours. April surprise: solved permanently.
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