Quarter Calculator

A calendar year is partitioned into four standard 3-month blocks known as quarters (Q1, Q2, Q3, and Q4). The standard Gregorian calendar divides the 365 days (or 366 days in a leap year) into quarters of 90 to 92 days each. Business performance, tax reporting, corporate SEC 10-Q filings, and GDP economic assessments rely heavily on quarterly accounting intervals.

Formula: Quarter Start = First day of month (3 * (Q - 1) + 1); Quarter End = Last day of month (3 * Q)

• Q1: January 1 through March 31 (90 days, or 91 days in leap years)
• Q2: April 1 through June 30 (91 days)
• Q3: July 1 through September 30 (92 days)
• Q4: October 1 through December 31 (92 days)

• Standard Q1 (Non-Leap Year): January (31 days) + February (28 days) + March (31 days) = 90 Total Days (~64 to 65 Working Days depending on weekends & holidays)
• Leap Year Q1 (e.g., 2024, 2028): January (31 days) + February (29 days) + March (31 days) = 91 Total Days (+1 additional working or weekend day)

Working days (business days) measure the operational capacity of a quarter. They equal the total days minus weekend days (Saturdays and Sundays) and minus official public/federal holidays that fall on a weekday. Under U.S. Office of Personnel Management (OPM) rules, if a federal holiday falls on a Saturday, it is observed on the preceding Friday; if it falls on a Sunday, it is observed on the following Monday.

Formula: Working Days = Total Quarter Days - Weekend Days - Observed Weekday Holidays

• Total Days: Number of elapsed calendar days between quarter start and quarter end, inclusive
• Weekend Days: Count of Saturdays and Sundays in the quarterly date span
• Observed Holidays: Federal holidays falling strictly on Monday through Friday (including weekend-shifted observed days)

While calendar quarters align strictly with January through December, many governments and multinational corporations operate on distinct fiscal years. For example, the United States Federal Government fiscal year begins on October 1 (making Q1 = Oct-Dec, Q2 = Jan-Mar, Q3 = Apr-Jun, Q4 = Jul-Sep). The United Kingdom government fiscal year begins on April 6, and Australia/New Zealand begins on July 1.