What Are the 4 Tax Quarters? Dates, Periods, and Why They Are Uneven
The four estimated tax periods are three, two, three, and four months long, so they are not really quarters at all. Here are the exact date ranges, the 2026 and 2027 deadlines, and which income belongs in which period.
The four estimated tax periods are January 1 to March 31, due April 15; April 1 to May 31, due June 15; June 1 to August 31, due September 15; and September 1 to December 31, due January 15 of the next year. They run three, two, three, and four months, so only the first is a real quarter. Income belongs to the period in which you were paid, and you only have to make payments at all if you expect to owe $1,000 or more for the year.
Key takeaways
- Only the first period matches a calendar quarter; the rest run two, three, and four months.
- For the 2026 tax year the deadlines are April 15, 2026, June 15, 2026, September 15, 2026, and January 15, 2027, and none of them shift this cycle.
- Income counts in the period you received it, not the period you did the work or sent the invoice.
- The $1,000 rule decides whether you owe estimated payments at all, and a W-2 job's withholding can absorb the liability instead.
- The penalty is computed period by period, which is why a big payment logged against the wrong quarter still costs you.
The four estimated tax periods for the 2026 tax year
| Period | Income earned | Payment due | Length |
|---|---|---|---|
| First | January 1 to March 31, 2026 | April 15, 2026 | 3 months |
| Second | April 1 to May 31, 2026 | June 15, 2026 | 2 months |
| Third | June 1 to August 31, 2026 | September 15, 2026 | 3 months |
| Fourth | September 1 to December 31, 2026 | January 15, 2027 | 4 months |
There are four, they have fixed date ranges, and only the first one is actually a quarter. The IRS divides the year into four estimated tax periods running three, two, three, and four months, because the due dates were fixed first and the periods were fitted around them afterward. Knowing the exact boundaries matters more than it sounds like it should, because the underpayment penalty is calculated period by period rather than on your total for the year.
The four periods and their deadlines
The first period covers January 1 through March 31 and is due April 15. The second covers April 1 through May 31 and is due June 15. The third covers June 1 through August 31 and is due September 15. The fourth covers September 1 through December 31 and is due January 15 of the following year. For the 2026 tax year that means April 15, 2026, June 15, 2026, September 15, 2026, and January 15, 2027. None of those fall on a weekend or a federal holiday, so none of them shift this cycle. When a due date does land on a Saturday, Sunday, or legal holiday, your payment is on time if you make it on the next business day.
Why the second period is only two months
Because the schedule was built around the 15th of April, June, September, and January, and the periods were drawn to fill the gaps between them. That leaves the second period covering only April and May and the fourth stretching across four months. Nothing about it is intuitive, and it is the single most common source of confusion for anyone who assumed a tax quarter meant three months. If you set aside a fixed amount every month, you are effectively overpaying the second period and underpaying the fourth.
Income belongs to the period you were paid
Not the period you did the work, and not the period you sent the invoice. A project finished in May and paid in June belongs to the third period, due September 15. This is the detail that catches people who front-load their year: a large payment received in one period can trigger a penalty for that period even though the annual total was covered, because each period is scored on its own. If your income is genuinely lumpy, the annualized income installment method on Form 2210 lets you match payments to when the money actually arrived instead of paying in four equal pieces.
Whether you have to pay at all
The test is whether you expect to owe $1,000 or more for the year after withholding and credits. Below that, no estimated payments are required. There is also a route around the schedule entirely: if you or a spouse has a W-2 job, raising the withholding there covers the liability, and withholding is treated as paid evenly across the year no matter when it happened, which retroactively fixes periods you already missed. Estimated payments do not work that way.
Know your number before the deadline
Vuuv tracks income and deductible expenses as they happen and keeps a running profit figure, so each period's payment is a number you look up rather than a guess you make in the last week.
Start freeMissing one is not a catastrophe
The underpayment penalty is interest on the shortfall, running from that period's due date until you pay it. It is not a flat fine and it does not invalidate the rest of your year. Paying late costs less than not paying, and sending the money as soon as you notice stops the meter on that amount. For the safe harbor rules that let you sidestep the calculation altogether, and for how to actually send a payment, see our guide to quarterly estimated taxes. If you are still working out what to reserve as you get paid, how much to set aside for taxes starts from the income side instead.
Frequently asked questions
What are the 4 tax quarters?
They are January 1 to March 31, due April 15; April 1 to May 31, due June 15; June 1 to August 31, due September 15; and September 1 to December 31, due January 15 of the following year. Despite the name, they run three, two, three, and four months, so only the first one lines up with a calendar quarter.
Why is the second tax quarter only two months long?
Because the due dates were set to fall on the 15th of April, June, September, and January, and the periods were then fitted to those dates rather than the other way around. The result is a second period that covers only April and May and a fourth that stretches across four months. It is a quirk of the schedule, not a mistake in your calendar.
What are the quarterly tax due dates for 2026?
April 15, 2026, June 15, 2026, September 15, 2026, and January 15, 2027. None of them land on a weekend or a federal holiday this cycle, so none shift. When a due date does fall on a Saturday, Sunday, or legal holiday, the payment is on time if you make it on the next business day.
Which quarter does my income belong in?
The one whose date range contains the day you actually received the money. Income from a job finished in May but paid in June belongs to the third period, due September 15, not the second. This matters because the penalty is calculated period by period, so a large payment in the wrong period can cost you even if your total for the year is right.
Do I have to pay all four?
Only if you expect to owe $1,000 or more for the year after withholding and credits. If your income is seasonal you can end up owing in some periods and not others, and if you have a W-2 job alongside your business you can often raise your withholding there instead and skip estimated payments entirely.
What happens if I miss one quarter?
You owe an underpayment penalty calculated as interest on the shortfall, running from that period's due date until you pay. Paying late is cheaper than not paying, and catching up in the next period stops the meter on the amount you send. Missing one period does not invalidate the rest of your year.
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This article is general information, not tax advice. Tax rules change and every situation is different. Confirm the details against current IRS guidance or talk to a qualified tax professional before you file.