Quarter date range
Gives the first and last day of a calendar quarter, how many days and weekdays it contains, and which months it spans.
How to use the quarter date range
Calendar quarters are unequal, which surprises people comparing quarter-on-quarter numbers. Q1 has 90 days (91 in a leap year), Q2 has 91, and Q3 and Q4 have 92 each. Q3 is therefore just over two per cent longer than Q1 — enough to move a revenue comparison by more than most of the changes anyone is trying to detect. Comparing daily averages rather than totals removes it.
The weekday count varies more, from about 62 to 66, and that matters more than the day count for anything driven by working days: support volume, billable hours, payroll. Two quarters with the same number of days can differ by three working days depending on where the weekends fall.
This is the calendar quarter. A fiscal quarter can start anywhere — the UK tax year begins on 6 April, the US federal year on 1 October, and many companies pick their own — so if your Q1 does not start on 1 January, this is the wrong tool and the right answer comes from your finance calendar.
Questions
No. Q1 has 90 days (91 in a leap year), Q2 has 91, Q3 and Q4 have 92 — over two per cent apart.