Fiscal quarters are the four three-month blocks that make up a company’s fiscal year, labeled Q1, Q2, Q3, and Q4 in the order they occur. They set the rhythm for financial reporting, budgeting, and tax payments, and because a fiscal year can begin in any month, one company’s Q1 may cover completely different months from another’s.
How Q1 Through Q4 Are Defined
Every fiscal year splits into four consecutive quarters of three months each. Q1 covers the first three months of whichever 12-month period a business has chosen as its fiscal year, Q2 the next three, and so on through Q4, which ends on the last day of the fiscal year. The labels give management, investors, and regulators a shared vocabulary for comparing performance across standardized intervals.
The value of quarters is the cadence they create. A single annual review lets problems fester for months before anyone notices. Quarterly checkpoints force teams to reconcile accounts, measure revenue against forecasts, and adjust spending while there is still time to course-correct. That matters most for seasonal businesses, where an annual snapshot can hide dramatic quarter-by-quarter swings in cash flow.
Fiscal Quarters vs. Calendar Quarters
Calendar quarters are fixed to the Gregorian calendar. Q1 runs January through March, Q2 April through June, Q3 July through September, and Q4 October through December. Every calendar-year business shares this schedule.
A fiscal quarter depends entirely on when the organization’s fiscal year begins. If a company starts its fiscal year on July 1, its Q1 covers July through September and its Q4 runs April through June. “Q3 earnings” from two different companies can describe completely different months, which trips people up more often than you would expect when comparing financial statements.
Businesses choose non-calendar fiscal years to line their reporting up with the natural rhythm of their operations. A retailer that closes its fiscal year on January 31 captures the full holiday sales season and the wave of January returns inside a single Q4, producing cleaner year-over-year comparisons. An organization whose busy season runs through the summer might end its fiscal year on September 30 for the same reason.
Common Fiscal Year Start Dates
The U.S. federal government begins its fiscal year on October 1 and ends it on September 30. That puts the government’s Q1 in October through December and its Q4 in July through September, which is why budget debates in September get described as year-end scrambles even though the calendar year is not close to finished.1NIH BRAIN Initiative. Fiscal Year
Many colleges and universities start their fiscal year on July 1 to align with the academic calendar. Some large retailers begin on February 1, so the prior year’s full holiday season and post-holiday returns land in the previous fiscal year’s Q4. When reading a public company’s financial statements, check the fiscal year-end date on the cover page of its annual report; it is a required disclosure on SEC Form 10-K.2SEC.gov. Form 10-K
The 52-53 Week Fiscal Year
Some businesses, particularly retailers and manufacturers, do not use a fiscal year that lands on the same calendar date each year. Instead, they elect a 52-53 week fiscal year that always ends on the same day of the week, such as the last Saturday in January or the Saturday nearest to January 31. The IRS authorizes this approach under federal regulations.3eCFR. 26 CFR 1.441-2 – Election of Taxable Year Consisting of 52-53 Weeks
Ending every fiscal period on the same weekday means each quarter contains exactly 13 complete weeks, making week-over-week sales comparisons far more reliable. Most companies using this method structure their quarters in a 4-4-5 pattern, where two months contain four weeks and one contains five. Some use 4-5-4 or 5-4-4 instead, but the total always adds up to 13 weeks per quarter.
The catch is arithmetic. 52 weeks is only 364 days, so about every five or six years the company must add a 53rd week to keep the fiscal year from drifting away from its reference calendar month. That extra week can distort quarterly comparisons, and companies typically flag it in their earnings reports.
Quarterly Reporting for Public Companies
Publicly traded companies in the United States must file quarterly financial reports on SEC Form 10-Q after each of the first three fiscal quarters. No 10-Q is required for the fourth quarter, because the annual report on Form 10-K covers the full fiscal year and takes its place.4eCFR. 17 CFR 240.13a-13 – Quarterly Reports on Form 10-Q
Filing deadlines depend on the company’s size, measured by public float (the market value of shares held by outside investors):
- Large accelerated filers with a public float of $700 million or more: 40 days after the fiscal quarter ends.5SEC.gov. Form 10-Q
- Accelerated filers with a public float between $75 million and $700 million: 40 days after the fiscal quarter ends.5SEC.gov. Form 10-Q
- All other filers, with a public float below $75 million: 45 days after the fiscal quarter ends.5SEC.gov. Form 10-Q
These deadlines are tight, and missing them triggers SEC enforcement consequences. Investors rely on the 10-Q for a timely picture of revenue, expenses, and cash flow, which is why quarterly earnings announcements move stock prices so sharply.
Estimated Tax Payments by Quarter
Fiscal quarters also set the schedule for estimated tax payments, but the rules differ for individuals and corporations. Mixing them up is one of the more common tax mistakes.
Individuals and Sole Proprietors
If you are self-employed, a freelancer, a partner in a partnership, or an S corporation shareholder receiving pass-through income, you generally must make quarterly estimated tax payments using Form 1040-ES when you expect to owe $1,000 or more for the year after subtracting withholding and refundable credits.6Internal Revenue Service. Estimated Taxes
For individual taxpayers, the quarterly deadlines follow the calendar year regardless of your business’s fiscal year:
- Q1 (January 1 – March 31): April 15
- Q2 (April 1 – May 31): June 15
- Q3 (June 1 – August 31): September 15
- Q4 (September 1 – December 31): January 15 of the following year
These “quarters” are not actually equal. Q2 covers only two months while Q3 covers three. The IRS designed the schedule around administrative convenience, not symmetry.7Internal Revenue Service. Estimated Tax
Missing a deadline can trigger an underpayment penalty even if you eventually get a refund when you file. You can avoid the penalty by paying at least 90% of the current year’s tax liability or 100% of the prior year’s tax through a combination of withholding and estimated payments. If your adjusted gross income exceeded $150,000 in the prior year ($75,000 if married filing separately), the prior-year safe harbor rises to 110%.8Internal Revenue Service. Underpayment of Estimated Tax by Individuals Penalty
Corporations
Corporations face a lower trigger: estimated payments are generally required when the corporation expects to owe $500 or more for the year.6Internal Revenue Service. Estimated Taxes And unlike individual deadlines, corporate estimated tax deadlines are based on the corporation’s own fiscal year, not the calendar year. Payments are due on the 15th day of the 4th, 6th, 9th, and 12th months of the corporation’s tax year.9Internal Revenue Service. Publication 509 (2026), Tax Calendars
For a calendar-year corporation, that works out to April 15, June 15, September 15, and December 15. Note the December deadline, which differs from the January 15 deadline that individuals face. A corporation with a July 1 fiscal year start would owe installments on October 15, December 15, March 15, and June 15 instead.
Changing Your Business’s Fiscal Year
Once a business adopts a fiscal year and files a tax return using it, that year is its established accounting period. Changing it requires IRS approval in most cases. The standard route is filing Form 1128, “Application to Adopt, Change, or Retain a Tax Year,” and demonstrating a legitimate business purpose for the switch.10eCFR. 26 CFR 1.442-1 – Change of Annual Accounting Period
The application is due by the due date of the federal income tax return for the short period created by the change. A short period is the gap between the end of your old fiscal year and the start of the new one, and you will need to file a separate tax return covering that abbreviated period.11Internal Revenue Service. Instructions for Form 1128 If the change creates a short period of six days or fewer (or 359 days or more) because you are switching to or from a 52-53 week year, no separate short-period return is required.12eCFR. 26 CFR 1.443-1 – Returns for Periods of Less Than 12 Months