How shifted quarters work
Choose July as the fiscal start, for example, and Q1 becomes July–September, Q2 October–December, Q3 January–March, and Q4 April–June.
Use calendar quarters (January–December) or set a shifted fiscal year.
Calendar quarters are fixed: Q1 begins January 1 and Q4 ends December 31. A fiscal quarter uses the same three-month structure but shifts Q1 to the organization’s fiscal start month.
| Quarter | Months | Usual dates |
|---|---|---|
| Q1 | January–March | January 1–March 31 |
| Q2 | April–June | April 1–June 30 |
| Q3 | July–September | July 1–September 30 |
| Q4 | October–December | October 1–December 31 |
Choose July as the fiscal start, for example, and Q1 becomes July–September, Q2 October–December, Q3 January–March, and Q4 April–June.
The same 12-month period can be named for the year in which it starts or ends. Always pair an FY label with exact dates when rules are unclear.
Use quarter ranges for reporting deadlines, budget cycles, sales targets, project milestones, academic planning, and period-over-period analysis.
This calculator only models four consecutive three-month quarters beginning on the first day of a month. It does not model week-based or irregular periods.
The quarter comes from a normalized month offset. Number January as 1 through December as 12:
fiscal month index = ((C − F + 12) mod 12), where C is the calendar month and F is the fiscal start month. The index runs from 0 to 11.quarter = floor(fiscal month index / 3) + 1.C ≥ F; otherwise it is the preceding year.quarter start = fiscal-year start + (quarter − 1) × 3 months. The quarter end is the calendar day immediately before the start plus three months.inclusive total days = quarter end − quarter start + 1. Gregorian month lengths automatically include February 29 in leap years.The modular form prevents negative offsets when a fiscal year crosses New Year. Calendar mode uses F = 1.
Inputs: date 2026-03-18, calendar mode (F = 1). Index ((3 − 1 + 12) mod 12) = 2, so floor(2 / 3) + 1 = Q1. The range is January 1–March 31, 2026: day 77 of 90, with 13 days after the selected date.
Inputs: date 2026-03-18, April start, year-it-ends naming. Index ((3 − 4 + 12) mod 12) = 11, so the date is in Q4 of FY2026. The fiscal year is April 1, 2025–March 31, 2026; Q4 is January 1–March 31, 2026, day 77 of 90 with 13 days remaining after the date.
Inputs: date 2026-01-01, October start, year-it-ends naming. Index ((1 − 10 + 12) mod 12) = 3, so the date is the first day of Q2 in FY2026. The fiscal year is October 1, 2025–September 30, 2026; Q2 is January 1–March 31, 2026, day 1 of 90 with 89 later days.
For calendar Q1 2026, January 1 returns day 1, week 1, and 89 later days. March 31 returns day 90, week 13, and 0 later days. Both boundary dates are included in the quarter.
The calculator loads your current local date and immediately identifies its calendar or fiscal quarter. Choose Calendar Quarter for the standard answer, or Fiscal Quarter and your organization’s start month for a shifted answer.
In a calendar year, Q1 is January–March, Q2 is April–June, Q3 is July–September, and Q4 is October–December. Fiscal quarters shift from the selected fiscal start month.
A calendar quarter is one of four fixed three-month periods in January–December. A fiscal quarter is one of four three-month periods measured from an organization’s chosen fiscal-year start month.
FY2026 may mean the fiscal year that ends in 2026 or the one that starts in 2026. Select the convention your organization uses; the result always shows the exact fiscal-year start and end dates.
A standard month-based quarter has 89, 90, 91, or 92 days depending on its months and whether February falls in a leap year. The calculator counts both the quarter start and end dates.
Yes. Every calendar day is included, including Saturdays, Sundays, and holidays. This is not a business-day calculation.
No. This calculator supports a fiscal year starting on the first day of any month. Confirm the start date and naming rule against your organization’s official calendar.
No. It supports four quarters made from three whole Gregorian calendar months each, not 4-4-5, 4-5-4, 5-4-4, 52/53-week, stub-year, 13-period, or April 6 tax-year calendars.
Method: The calculator uses the proleptic Gregorian calendar and groups three complete calendar months into each quarter. The IRS definition of tax years describes a calendar year as January 1–December 31 and a fiscal year as 12 consecutive months ending on the last day of a month other than December.
Check your official calendar: Tax, accounting, government, and organizational conventions vary. Verify results before filing or reporting. This tool does not calculate 4-4-5, 4-5-4, 5-4-4, 52/53-week, 13-period, stub-year, retail, or April 6 tax-year calendars.