4-4-5 calendar
The 4–4–5 calendar is a method of managing accounting periods. The 4–4–5 calendar divides a year into four quarters of 13 weeks grouped into two 4-week "months" and one 5-week "month".
 | A quarter could either be: 4-4-5, 5-4-4 or 4-5-4 weeks. |
A major advantage over a regular calendar is that the end date of the period is always the same day of the week, which is useful for a shift of planning as every period is the same length.
Because the 4–4–5 calendar only has 364 days (7 x 52), a 53rd week will need to be added every five or six years, which can make year-on-year comparison difficult.
| | • The 53rd week is always the last month of the year (4-4-6, 5-4-5 or 4-5-5 weeks). • When using the Strict 52 calendar setting, the year always contains exactly 52 weeks by definition. |