The 4–4–5 calendar is a method of managing accounting periods. It is a common calendar structure for some industries, such as retail, manufacturing and parking industry. The 4–4–5 calendar divides a year into 4 quarters. Each quarter has 13 weeks which are grouped into two 4-week "months" and one 5-week "month". The grouping of 13 weeks may be set up as 5–4–4 weeks or 4–5–4 weeks , but the 4–4–5 seems to be the most common arrangement.