If you work for yourself or operate a small business without employer withholding, income tax is generally paid four times a year, not only in April. A missed payment can create an underpayment penalty over the year, plus an April balance that many founders are not ready to cover.
The 2026 estimated tax dates follow the usual schedule. Each falls on a weekday, so no federal holiday changes apply. Here are the deadlines and periods covered:
| Payment | Due Date | Income Period Covered |
|---|---|---|
| Q1 | April 15, 2026 | January 1 through March 31, 2026 |
| Q2 | June 15, 2026 | April 1 through May 31, 2026 |
| Q3 | September 15, 2026 | June 1 through August 31, 2026 |
| Q4 | January 15, 2027 | September 1 through December 31, 2026 |
Two table details matter. Q2 covers just April and May, while Q3 and Q4 cover three months each. That is how the IRS sets its installment periods, so June income counts toward Q3 estimated taxes. Q4 is due in January 2027, after the tax year ends. For founders with their strongest quarter in Q4, it can be the largest payment and the easiest one to miscalculate.
"Estimated" Does Not Mean "Guessed"
Many founders hear "estimated" and treat quarterly payments as rough numbers to fix in April. That can be costly. Underpayment penalties are assessed by quarter, not as one total at filing. If Q1 and Q2 payments were short, their penalty periods began in April and June, even if you later make up the difference.
You do not need perfect precision. The IRS offers two ways to avoid underpayment penalties, and self-employed founders should understand both.
Safe harbor: Pay 100% of your prior-year tax liability, or 110% if prior-year adjusted gross income exceeded $150,000, split across four installments. If your 2025 return showed $18,000 in federal income and self-employment taxes, paying $4,500 each quarter in 2026 avoids underpayment penalties, regardless of 2026 earnings.
Annualized income installments: Base each payment on actual year-to-date income through that period. It takes more quarterly work with IRS Form 2210, Annualized Income Installment Method, but can lower payments when current income trails the prior-year average. It often helps founders with uneven income.
Safe harbor skips income forecasting. You only need your prior-year tax liability, found on your 2025 return at line 24 of Form 1040. Divide it by four and track the four dates above. That is the minimum payment needed to avoid penalties.
Prepare for Each Deadline
Each payment calls for a slightly different check. Here is what to prepare.
April 15 (Q1): Your 2025 annual return is also due, making this the busiest date. An extension delays the annual return, not the Q1 estimated payment. They are separate obligations on one date. Q1 covers January through March income. If revenue resembled prior-year Q1, the safe-harbor amount is a reasonable guide.
June 15 (Q2): This payment covers April and May only. Strong Q2 income may make the safe-harbor amount too low. With the annualized method, use April-May income in the Form 2210 worksheet for a closer figure. Even with safe harbor, review year-to-date net income by early June to see whether a catch-up is needed.
September 15 (Q3): This covers June, July, and August. You have a clearer view of annual income by then. A late-August full-year projection can estimate the 2026 tax bill and show whether the four payments will cover it. If Q3 is strong, paying more then can reduce the January balance.
January 15, 2027 (Q4): This covers September through December. It is often the largest payment when Q4 is your strongest quarter, and it follows the holidays. Prepared founders set aside part of each Q4 deposit instead of treating December cash as available to spend.
When Q1 Income Arrives Late
A project or consulting business may have strong Q1 revenue while large invoices go unpaid until April or May. On the cash basis, the Q1 payment is already due when that money arrives, and the cash can feel like current-quarter income rather than payment for earlier work.
Cash-basis income counts when received. A January invoice paid in April is April income, not January income. Q1 therefore includes receipts from January 1 through March 31 only. Cash received later for January work is Q2 income, included with the June 15 payment.
The annualized method can help here. If slow client payments kept Q1 receipts low, it may produce a smaller Q1 payment. The catch-up occurs in Q2 when the cash arrives.
State Taxes Have Their Own Calendar
Most states with income tax also require quarterly estimates from self-employed people and small business owners. State dates may match the federal schedule, but not always. California uses April, June, September, and January payments with different allocations: 30% in April, 40% in June, 0% in September, and 30% in January under the CalFTB schedule. Washington has no personal income tax, but its B&O tax has a separate filing cadence for businesses above certain revenue thresholds.
This guide covers federal estimates. Use your state's revenue department for state deadlines and calculation rules. The calendars are separate, and a missed state payment may bring penalties apart from federal obligations.
How Uprise Handles This
Uprise reviews your bookkeeping data each quarter, using year-to-date income and prior-year liability to calculate an estimated payment. Before each deadline, you receive the amount, due date, and IRS payment link. You make the payment, while we calculate it. Whether you use Uprise or Form 1040-ES, run the numbers before each deadline, not for the first time in April.
Quarterly estimates are not optional for self-employed people whose yearly tax liability exceeds $1,000. A routine built around the four dates above is easier than sorting out penalty math in April.