Calendar Adjustment Day - Calendar Adjustment Day marks a pivotal date in history on which the calendar system changed forever. Find out more here.

Calendar Adjustment Day 2024 – September 2, 2024

Calendar Adjustment Day on September 2 is more than just making some tweaks to your calendar. It commemorates the date in history when New Year’s Day was shifted to the first of January, and the entire calendar system changed.

History of Calendar Adjustment Day

After the British Calendar Act of 1751, the Gregorian Calendar was adopted by Britain in 1752. But shifting and aligning with the new calendar was not that simple — it required omitting 11 days for synchronization with the proposed Gregorian Calendar. The residents of Britain and the American colonies went to sleep at night on September 2, 1752, and woke up the next day to September 14, 1752. This change also led to New Year’s Day being celebrated on January 1. Those 11 days are lost forever in time.The calendar adjustment wasn’t taken too well by the public, who felt cheated and demanded to have their 11 days back. It was necessary to skip these 11 days in September so that Britain could align with the Julian calendar, like most of Europe.Many historians claim that the change in calendar led to rioting and civil unrest, demanding “Give us our 11 days.” Many people also believed that their lives were shortened by 11 days. The moving of some holy days and holidays like Easter was also seen as suspicious and the new dates were considered “incorrect.”To avoid confusion, colonial records use the terminologies ‘Old Style’ and ‘New Style’ to differentiate between dates in history. These dates are denoted by using a slash mark (/).The changeover involved a number of different steps. First, the last day of the month, December 31, 1750, was succeeded by January 1, 1750. Before, December was the 10th month in the Old Style calendar, and January was the 11th. Next, changes were made to March 24. Previously, March 25 was considered the start of the New Year in the Old Style calendar. The next change was January 1, 1752 following December 31, 1751. As stated before, the new year started with March 25 in the Old Style year. Lastly, September 2, 1752 was followed by September 14, 1752. This is the part where 11 days from the year were omitted.

Calendar Adjustment Day timeline

The Gregorian Calendar

Pope Gregory XIII introduces the Gregorian calendar.

1582 — 1751
Two Calendars

Two calendars are in use across Europe — the Julian Calendar and the Gregorian Calendar.

The British Calendar Act

The British Calendar Act brings about changes to the calendar.

11 Days Are Lost

The days between September 2 and September 14 are skipped on the calendar.

Calendar Adjustment Day FAQs

What is the reason the calendar for September of 1752 is missing 11 days?

The Gregorian calendar was 11 days ahead of the Julian calendar. When the former was adopted in 1752, 11 days had to be skipped to avoid discrepancies and accurately align the dates.

When did we lose 11 days?

The 11 days of September 1752 from September 3 to September 13 are considered to be the ‘lost’ days.

Who invented the calendar we use today?

Pope Gregory XIII is credited with introducing the Gregorian calendar in 1582.

How to Observe Calendar Adjustment Day

  1. Buy a new calendar

    We all maintain digital calendars on our smartphones and laptops now, but it doesn’t beat the ease and convenience of a desk calendar. Pick a themed calendar for an added touch.

  2. Mark special events

    If you don’t use your calendar frequently, today is a good time to start. It is a great way to organize your tasks and remember important appointments and birthdays!

  3. Find relevant content

    The 11 missing days of 1751 are referred to in several works of fiction, such as “Foucault’s Pendulum” by Umberto Eco, “Slammerkin'' by Emma Donoghue, and in the eighth season of the adventures series of “Doctor Who.”

5 Facts About The Gregorian Calendar

  1. The original intent

    The Gregorian calendar was created with the intention of changing the date of Easter, which wasn’t proving to be accurate on the flawed Julian calendar.

  2. Pope Gregory didn’t design the Gregorian calendar

    Even though he is considered the authority behind the new calendar, he commissioned physician Aloysius Lilius and astronomer Christopher Clavius to design it.

  3. The first printed Gregorian calendar

    “Lunario Novo secondo la nuova riforma” is among the earliest printed editions of the Gregorian calendar in 1582.

  4. Resistance to the new calendar

    The new calendar was met with resistance from Protestants, some of whom viewed it as a satanic agenda.

  5. Astronomers don’t use the Gregorian calendar

    As noted by the Galileo Project, “the Gregorian Calendar is useless for astronomy because it has a 10-day hiatus in it — to calculate positions backward in time, astronomers use the Julian Date.”

Why Calendar Adjustment Day is Important

  1. It’s a cool event in history

    Many of us don’t know about this event in history. It’s these little things that just seem to have been set in place, but have a great history in terms of how they were gradually implemented.

  2. Appreciating time

    The value of time is reiterated on Calendar Adjustment Day. In the same way that the people of colonial Britain lost their 11 days, every moment that we waste and don’t enjoy is being lost to the sands of time.

  3. We love calendars

    National Today is all about days of the year so of course, how can we not love the calendar?

Calendar Adjustment Day dates

Year Date Day
2023 September 2 Saturday
2024 September 2 Monday
2025 September 2 Tuesday
2026 September 2 Wednesday
2027 September 2 Thursday