Fiscal Quarter End Date Calculator
A fiscal year is split into four quarters, but the quarters depend on which month your fiscal year begins. The US federal fiscal year starts in October; many companies use January, April, or July. Enter a date and your fiscal year start month, and the calculator tells you which quarter the date falls in along with that quarter's start and end dates.
How the fiscal quarter is found
months since fiscal year start = (month - start month + 12) mod 12
quarter = floor(months since start / 3) + 1
quarter start month = start month + (quarter - 1) * 3
quarter end = last day of (quarter start month + 2)
The end date is the final calendar day of the third month of the quarter, computed with correct month lengths and leap years.
Worked example
With a fiscal year starting in October (start month 10), a date of 15 November falls in Q1, which runs 1 October to 31 December. A date of 15 March would fall in Q2, which runs 1 January to 31 March.
Fiscal quarters: frequently asked questions
What is a fiscal quarter?
A fiscal quarter is a three-month accounting period. A fiscal year is divided into four quarters: Q1, Q2, Q3, and Q4. The quarters are defined relative to the fiscal year start month, which is not always January.
Why does the fiscal year start month matter?
Many organisations do not use a calendar fiscal year. The US federal government's fiscal year starts 1 October, so its Q1 runs October to December. Choose the start month your organisation uses, and the calculator aligns the four quarters accordingly.
How is the quarter end date found?
Once the start month is known, the quarter containing your date is the three-month block it falls into. The quarter end date is the last day of the third month of that block, accounting for month lengths and leap years.
What start month should I use for a calendar fiscal year?
Enter 1 for January. Then Q1 is January to March, Q2 is April to June, Q3 is July to September, and Q4 is October to December, matching the standard calendar quarters.
Official sources
- U.S. Government Accountability Office, federal fiscal year: gao.gov.
- Quarter arithmetic follows the standard Gregorian calendar.
Reviewed by the CalculatorHub team, edited by James Graham, 19 June 2026. See our methodology.