In British and Irish tradition, quarter days are four specific dates each year when workers were hired, school terms began, and rent payments were required. These dates aligned with four religious holidays, spaced about three months apart and near the two solstices and two equinoxes.

Today, the importance of quarter days is much smaller, though rent payments for some properties in England still follow the old English quarter days.

Quarter days have been celebrated since at least the Middle Ages. They required people to settle debts and resolve legal disputes, as accounts had to be settled and recorded publicly on these dates.

England and Wales

To help remember when the quarter days occur, a helpful memory trick is to count the letters in the names of the months. For example, March has five letters, so its quarter day is on the 25th. June has four letters, so its quarter day is on the 24th. September has nine letters, so its quarter day is on the 29th.

The English quarter days (also used in Wales and the Channel Islands) are special dates tied to the calendar. Lady Day, which happens near the Spring equinox, was the start of the year in England, Wales, and the British dominions (but not Scotland) until 1752. That year, the practice was changed to match Scotland’s tradition of starting the year on January 1. Today, the British personal tax year still ends on "Old" Lady Day, which is May 5 in the modern (Gregorian) calendar. This date was set in 1750 when the calendar was changed by moving the dates forward by 11 days.

Between the quarter days are four holidays called cross-quarter days. These include Candlemas on February 2, May Day on May 1, Lammas on August 1, and All Hallows on November 1.

At many schools, terms often begin on the quarter days. For example, the autumn term starts on September 29 and is sometimes called the Michaelmas term, especially at older universities.

Ireland

Before the Christianization of Ireland in the 5th century AD, the Celtic quarter days were celebrated. These days are now called cross-quarter days because they happen about halfway into each of the English quarters. Since 2022, when a holiday for Imbolc was added, all four traditional Celtic quarter days now have a public holiday in the Republic of Ireland each year, on a Monday near the actual dates.

Scotland

The "Old Scottish term days" matched roughly the old Celtic quarter days. These were also the dates of the Quarter Days used in northern England until the 18th century. The dates for removals and hiring servants for Whitsunday and Martinmas were changed in 1886 to 28 May and 28 November, respectively. The Term and Quarter Days (Scotland) Act 1990 revised the "Scottish term days" for official use as: The Act states that the new dates began on 13 June 1991 (12 months after the Act was passed). This means the Scottish term days, which are used for paying rent, now align more closely with cross-quarter days than with English quarter days.

In other countries

In Germany during the late 18th century, renting property often began on Easter or on one of the quarter days, which included Midsummer Day, Michaelmas, or Christmas.