Calendar reform is any proposed reform of a calendar.

Historically, most calendar reforms have been made in order to synchronize the calendar in use with the astronomical year (either solar or sidereal) and/or the synodic month in lunar or lunisolar calendars. Look up Month in Wiktionary, the free dictionary. ...

The Gregorian calendar is currently used by most of the world. It was the consequence of Pope Gregory XIII's reform of the Julian calendar, which was, itself, the reform under Julius Caesar of the existing Roman calendar. The Gregorian calendar is the calendar that is used nearly everywhere in the world. ... Gregory XIII, born Ugo Boncompagni (January 7, 1502 – April 10, 1585) was pope from 1572 to 1585. ... The Julian calendar was introduced in 46 BC by Julius Caesar and came into force in 45 BC (709 ab urbe condita). ... Gāius Jūlius Caesar (IPA: ;[1]), July 12 or July 13, 100 BC – March 15, 44 BC) was a Roman military and political leader and one of the most influential men in world history. ... The Roman calendar changed its form several times in the time between the foundation of Rome and the fall of the Roman Empire. ...

Subsequent proposals have since been made to make the Gregorian calendar more useful.

Historical reforms

Most reforms for calendars have been to make them more accurate. This has happened to various lunar and lunisolar calendars and also the Julian calendar when it was modified into the Gregorian calendar.

Reform of lunar and lunisolar calendars

There have been 50 to 100 reforms of the traditional Chinese calendar over 2500 years, most of which were intended to better fit the calendar months to astronomical lunations and to more accurately add the extra month so that the regular months maintain their proper seasonal positions, even though each seasonal marker can occur anywhere within its month. There have been at least four similar reforms of the lunisolar version of the Hindu calendar, all intended to make the month a better match to the lunation and to make the year a better fit to the sidereal year. There have been reforms of the 'solar' version of the Hindu calendar which changed the distribution of the days in each month to better match the length of time that the Sun spends in each sidereal zodiacal sign. The same applies to the Buddhist calendar. The first millennium reform of the Hebrew calendar changed it from an observational calendar into a calculated calendar. The Islamic calendar was a reform of the preceding lunisolar calendar which utterly divorced it from the solar year. The Chinese calendar (Traditional Chinese: , Simplified Chinese: , pinyin: nónglì) is a lunisolar calendar, akin to the Hebrew calendar, incorporating elements of a lunar calendar with those of a solar calendar. ... A page from the Hindu calendar 1871-72. ... The Buddhist calendar is used on mainland southeast Asia in the countries of Cambodia, Laos, Thailand, and Myanmar (formerly Burma) in several related forms. ... The Hebrew calendar (Hebrew: ) or Jewish calendar is the annual calendar used in Judaism. ... The Islamic calendar or Muslim calendar (Arabic: التقويم الهجري; at-taqwīm al-hijrī; Persian: تقویم هجری قمری Gāhshomāri-ye Hejri; also called the Hijri calendar) is the calendar used to date events in many predominantly Muslim countries, and used by Muslims everywhere to determine the proper day on which to celebrate Islamic...

Julian/Gregorian reforms

At the time at which Julius Caesar took power in Rome, the Roman calendar had ceased to reflect the year accurately. The provision of adding an intercalary month to the year when needed had not been applied consistently, because it affected the length of terms of office. Intercalation is the insertion of an extra day, week or month into some calendar years to make the calendar follow the seasons. ...

The Julian reform lengthened the months (except February, owing to its religious significance) and provided for an intercalary day to be added every four years to February, creating a leap year. Intercalation is the insertion of an extra day, week or month into some calendar years to make the calendar follow the seasons. ... A leap year (or intercalary year) is a year containing an extra day, week or month in order to keep the calendar year synchronised with the astronomical or seasonal year. ...

William Hogarth's "An Election Entertainment" includes a banner with the protest slogan against the Gregorian calendar: "Give us our Eleven days"

This produced a noticeably more accurate calendar, but it was based on the calculation of a year as 365 days and 6 hours. In fact, the year is 11 minutes less than that. This had the effect of adding three-quarters of an hour to a year, and the effect accumulated. By the sixteenth century, the vernal equinox fell on March 10. Image File history File links Download high resolution version (2024x1607, 264 KB) Painting by William Hogarth, ca. ... Image File history File links Download high resolution version (2024x1607, 264 KB) Painting by William Hogarth, ca. ... William Hogarth (November 10, 1697 – October 26, 1764) was a major English painter, printmaker, pictorial satirist, and editorial cartoonist who has been credited as a pioneer in western sequential art. ... March 10 is the 69th day of the year in the Gregorian Calendar (70th in leap years). ...

Under Pope Gregory XIII, two reforms were effected: ten days were dropped from one year, to bring the calendar back into synchronization, and then to have century years, which are divisible by four, nevertheless not be leap years unless they are also divisible by 400. While this does not synchronize the years entirely, it would require 35 centuries to accumulate a day.

This reform slowly spread through the nations that used the Julian calendar, although the Russian church year still uses the Julian calendar. The times varied so widely that some countries had to drop more than ten: Great Britain, for instance, dropped eleven.

When noting dates occurring within the period, "Old Style" and "New Style" are used to distinguish which calendar was used by the person who recorded the date.

The existing calendar

Reformers cite several problems with the Gregorian calendar:

• It is not perpetual. Each year starts on a different day of the week, and calendars expire every year.
• Months are not equal in length, requiring the mnemonic rhyme, "Thirty days hath September…" to remember which month is 28, 29, 30, or 31 days long.
• It is difficult to determine the weekday of any given day of the year.
• The year’s four quarters are not equal. Business quarters that are equal would make accounting easier.
• Its epoch (origin) is not religiously neutral. The same applies to month and weekday names in many languages.
• Each month has no connection with the Moon.

A mnemonic (pronounced in Received Pronunciation) is a memory aid, and most serve an educational purpose. ... Thirty days hath September is a mnemonic rhyme commonly used in English-speaking countries to remember the lengths of the months in the Julian and Gregorian calendars. ... In chronology, an epoch is an instant chosen as the origin of a particular time scale. ... Look up Month in Wiktionary, the free dictionary. ... Weekdays are the days of the week which are not part of the weekend, i. ...

Perpetual calendars

Many calendar reforms have offered solutions to make the calendar perpetual. These reforms would make it easy to work out the day of week of a particular date, and would make changing calendars each year unnecessary. A perpetual calendar is a calendar which is good for a span of many years, such as the Runic calendar. ... A week is a [ PER [unit]] of time longer than a day and shorter than a month. ... Note that this article includes some hyperlinked dates whose format is configurable in Special pages | Preferences. What you see may not be what the author intended. ...

These make it easier to work out the day of week by having exactly 52 weeks in each year plus an extra day not belonging to any week and also having the leap day outside of any week.

For example, The World Calendar and the International Fixed Calendar are proposals that start each month on a Sunday. The remaining 364 days then form 52 weeks of 7 days. The World Calendar has every third month beginning on the same day of week. The World Calendar is a proposed reform of the Gregorian calendar created by Elisabeth Achelis of Brooklyn, New York in 1930. ... The International Fixed calendar (also known as the International Perpetual calendar, the Cotsworth plan, the Eastman plan, the 13 Month calendar or the Equal Month calendar) is a proposal for calendar reform providing for a year of 13 months of 28 days each, with one day at the end of...

Both of these calendars treat one or two days (the 365th day, and the 366th leap year day) each year as outside of any week or month in order to keep the calendar perpetual. In The World Calendar, these days are considered holidays and named Worlds Day and Leap Year Day. These "off-calendar", or "intercalary", days stand outside the seven-day week and caused some religious groups to strongly oppose adoption of The World Calendar. Such concerns helped prevent The World Calendar from being adopted in the 1940s and 1950s. A leap year (or intercalary year) is a year containing an extra day, week or month in order to keep the calendar year synchronised with the astronomical or seasonal year. ...

Supporters of The World Calendar, however, argue that the religious groups' opposition overlooked every individual's right to celebrate these holidays as extra days of worship, or Sabbaths. This option, they reason, maintains the seven-day worship cycle for those who share that concern, while allowing benefits of a perpetual calendar to be shared by all.

Some calendar reform ideas, such as the Pax Calendar, Bonavian Civil Calendar, New Earth Calendar, Symmetry454 calendar and the Common-Civil-Calendar-and-Time Calendar, were created to solve this problem by having years of either 364 days (52 weeks) or 371 days (53 weeks), thus preserving the 7-day week. The Pax calendar was invented by James A. Colligan in 1930 as a reform of the Gregorian calendar. ... The New Earth Calendar is a proposal for calendar reform by James A. Reich providing for a perpetual 364-day year of 13 identical months of 28 days each. ... The Symmetry454 Calendar (Sym454) is a proposal for calendar reform proposed by Dr. Irv Bromberg of the University of Toronto. ... The Common-Civil-Calendar-and-Time calendar (C&T) is a proposal for calendar reform. ...

These calendars add a leap week of seven days to the calendar every five or six years to keep the calendar roughly in step with the tropical year. The leap week calendar is a reformed calendar system with a whole number of weeks every year, and with every year starting on the same weekday. ... A tropical year is the length of time that the Sun, as viewed from the Earth, takes to return to the same position along the ecliptic (its path among the stars on the celestial sphere). ...

The Bonvaian Civil and Symmetry454 calendars have months of 28 and 35 days, and a leap week in December, when needed. The Common-Civil-Calendar-and-Time Calendar has months of 30 and 31 days, but includes an occasional 7-day leap week named “Newton”.

The 53-week calendar, used in government and in business for fiscal years, is a variant of this concept. Each year of this calendar can be up to 371 days long.

Still other proposals, like the 30x11 Calendar, abandon attempts to make the calendar perpetual, instead opting for eleven 30-day months and one "long month" of December at 35 days, or 36 days in leap years. The 30x11 (Thirty-eleven) Calendar is a calendar reform of the Gregorian calendar proposed by Stephen Abbott, a public relations consultant and writer in Manchester, New Hampshire. ...

13-month calendar proposals

Some calendar reformers seek to equalize the length of each month in the year. This is accomplished by creating a calendar that has 13 months of 28 days each, making 364 days.

An early 13-month proposal was the 1849 Positivist calendar, created by Auguste Comte. It was based on a 364-day year which included one or two "blank" days. Each of the 13 months had 28 days and exactly four weeks, and each started on a Monday. The International Fixed Calendar is a more modern descendant of this calendar. The positivist calendar was a proposal for calendar reform proposed by Auguste Comte in 1849. ... Auguste Comte (full name: Isidore Marie Auguste François Xavier Comte; January 17, 1798 - September 5, 1857) was a French thinker who coined the term sociology. ...

Another example of the use of "blank" days is the 13 moon calendar, which views the uncounted 365th and 366th days as "days out of time". The 13 Moon Calendar is based on a simple, natural rhythm of 13 Moons of 28 Days + a Day Out of Time for global celebration of Peace Through Culture. ...

Some proposals, such as the Sol Calendar, add one or two days to the calendar each year to account for the annual solar cycle, while others keep these days off the calendar entirely, to make the calendar perpetual. The 13-month Sol Calendar is a proposal for calendar reform by Jim Eikner of Austin, Texas, providing for a year of 13 months in length, with 12 contiguous months having 28 days each, with the final month of the year, December, having 29. ...

Around 1930 Colligan invented the Pax Calendar, which avoids off-calendar days by adding a 7-day leap week to the perpetual 364-day year for 71 out of 400 years. The New Earth Calendar does likewise by adding a leap week once every 5 years with exceptions. The Pax calendar was invented by James A. Colligan in 1930 as a reform of the Gregorian calendar. ... The New Earth Calendar is a proposal for calendar reform by James A. Reich providing for a perpetual 364-day year of 13 identical months of 28 days each. ...

The 13-month calendar loses appeal with some when it is realized that it actually destroys quarters. Adding the 13th month is considered by some to be a disadvantage because the disruption it causes results in more problems than the calendar it aspires to replace.

Lunisolar proposals

The Hermetic Lunar Week Calendar is a lunisolar calendar proposal which has 12 or 13 lunar months of 29 or 30 days a year, and begins each year near the vernal equinox. The Hermetic Lunar Week Calendar (HLWC) is a proposal for calendar reform by Peter Meyers. ... Illumination of Earth by Sun on the day of equinox The vernal equinox (or spring equinox) marks the beginning of astronomical spring. ...

The Simple Lunisolar Calendar uses 12 or 13 lunar months of 30 or 29 days with fixed lengths, and begins each year between Gregorian December 3 and January 1. The Simple Lunisolar Calendar is a proposal for calendar reform by Robert Pontisso. ... December 3 is the 337th (in leap years the 338th) day of the year in the Gregorian calendar. ... January 1 is the first day of the calendar year in both the Julian and Gregorian calendars. ...

The Rectified Hebrew calendar uses a more accurate leap month cycle of 4366 months every 353 years, intended to replace the 19-year cycle of the modern Hebrew calendar. The Rectified Hebrew calendar is a proposal for calendar reform by Dr. Irv Bromberg. ... The Hebrew calendar (Hebrew: ) or Jewish calendar is the annual calendar used in Judaism. ...

The Meyer-Palmen Solilunar Calendar has 12 lunar months with 29 or 30 days plus a leap month called Meton every 3 or 2 years with 30 or 31 days. 60 years together are called a cycle. It uses a leap cycle which has equal number of days, weeks, months, years and cycles. 2498258 days, 356894 weeks, 84599 months, 6840 years and 114 cycles nearly all equal each other!!! It is called an era but time isn't divided into it in this calendar but the 60-year cycle does divide time. The Meyer-Palmen Solilunar Calendar is a proposal for calendar reform by Peter Meyer and Karl Palmen. ... Meton of Athens was a mathematician, astronomer and engineer who lived in Athens in the 5th century BCE. He is best known for the 19-year Metonic Cycle which he introduced into the Athenian luni-solar calendar as a method of calculating dates. ...

Naming reform proposals

Calendar proposals that introduce a thirteenth month or change the Julian-Gregorian system of months often also propose new names for these months. New names have also been proposed for days out of the week cycle (e.g. 365th and leap) and weeks out of the month cycle. In The World Calendar, for example, the last day of the year is "Worldsday".

Proposals to change the traditional month and weekday names are less frequent. The Gregorian calendar obtains its names mostly from gods of now obsolete religions (e.g. Thursday from Nordic Thor or March from Roman Mars) or leaders of vanished empires (July and August from the first Cæsars), or ordinals that got out of synchronization (September through December, originally seventh through tenth, now ninth through twelfth). The god Thor, after whom Thursday is named. ... Thors battle against the giants, by MÃ¥rten Eskil Winge, 1872 Thor (Proto-Germanic: *Þunraz, Old Norse: Þórr, Old English: Þunor, Old Dutch and Old High German: Donar) is the red-haired and bearded god of thunder in Norse Mythology and more generally Germanic mythology. ... March is the third month of the year in the Gregorian Calendar and one of seven Gregorian months with the length of 31 days. ... Mars was the Roman god of war, the son of Juno and a magical flower (or Jupiter). ... Look up July in Wiktionary, the free dictionary. ... August is the eighth month of the year in the Gregorian Calendar and one of seven Gregorian months with the length of 31 days. ...

Calendar reformers, therefore, seek to correct what they see as deficiencies by focusing on more homogeneous sets of individuals, who usually share common traits.

Comte's Postitivst calendar, for example, proposed naming the 13 months in his calendar after figures from religion, literature, philosophy and science: Moses, Homer, Aristotle, Archimedes, Caesar, Saint Paul, Charlemagne, Dante, Gutenberg, Shakespeare, Descartes. Moses with the Tablets, 1659, by Rembrandt Moses or Mosheh (Hebrew: מֹשֶׁה Standard Tiberian ; Arabic: موسى, ; Geez: ሙሴ Musse) was an early Biblical Hebrew religious leader, lawgiver, prophet, and historian. ... Homer (Greek Hómēros) was a legendary early Greek poet and aoidos (singer) traditionally credited with the composition of the Iliad and the Odyssey. ... Aristotle (Greek: Aristotélēs) (384 BC – March 7, 322 BC) was an ancient Greek philosopher, a student of Plato and teacher of Alexander the Great. ... Archimedes (Greek: ; c. ... Gāius Jūlius Caesar (IPA: ;[1]), July 12 or July 13, 100 BC – March 15, 44 BC) was a Roman military and political leader and one of the most influential men in world history. ... Paul of Tarsus (b. ... A portrait of Charlemagne by Albrecht Dürer that was painted several centuries after Charlemagnes death. ... Dante in a fresco series of famous men by Andrea del Castagno, ca. ... This article or section is missing references or citation of sources. ... Wikipedia does not yet have an article with this exact name. ... René Descartes (March 31, 1596 – February 11, 1650), also known as Cartesius, was a highly influential French philosopher, mathematician, and scientist. ...

Similarly, the Hermetic Lunar Week Calendar uses 12 or 13 lunar months named after 13 pioneers in contributors to research for physioactive plants and chemicals: Artaud; Benjamin; Clark; De Quincy; Ellis; Furst; Grof; Hofmann; Izumi; Janiger; Kesey; Lilly; and leap month McKenna. The Hermetic Lunar Week Calendar (HLWC) is a proposal for calendar reform by Peter Meyers. ... Antonin Artaud Antonin Artaud (September 4, 1896–March 4, 1948) was a playwright, actor, and director. ... Walter Benjamin (July 15, 1892 – September 27, 1940) was a German Marxist literary critic, essayist, translator, and philosopher. ... Thomas de Quincey from the frontispiece of Revolt of the Tartars, Thomas de Quincey (August 15, 1785 – December 8, 1859) was an English author and intellectual. ... Henry Havelock Ellis (February 2, 1859 - July 8, 1939), known as Havelock Ellis, was a British doctor, sexual psychologist and social reformer. ... Stanislav Grof (born 1931 in Prague, Czechoslovakia) is one of the founders of the field of transpersonal psychology and a pioneering researcher into the use of altered states of consciousness for purposes of healing, growth, and insight. ... Dr. Dr. Albert Hofmann (born January 11, 1906) is a prominent Swiss scientist best known as the father of LSD. He was born in Baden, Switzerland, and studied chemistry at the University of Zürich. ... Dr. Oscar Janiger was a University of California Irvine Psychiatrist who was best known for his LSD research, which lasted from 1954 to 1962. ... Kenneth Elton Kesey (September 17, 1935 – November 10, 2001) was an American author, best known for his novel, One Flew Over the Cuckoos Nest, and as a (counter) cultural figure who, some consider, was a link between the beat generation of the 1950s and the hippies of the 1960s. ... John Lilly John Cunningham Lilly (January 6, 1915 – September 30, 2001) was an American physician, psychoanalyst and writer. ... Terence Kemp McKenna (November 16, 1946 – April 3, 2000) was a writer and philosopher. ...

The Simple Lunisolar Calendar names its months after the letters of the Greek alphabet: Alpha; Beta; Gamma; Delta; Epsilon; Zeta; Eta; Theta; Iota; Kappa; Lambda; Mu; and leap month Nu. The Simple Lunisolar Calendar is a proposal for calendar reform by Robert Pontisso. ... Because of technical limitations, some web browsers may not display some special characters in this article. ... Alpha (uppercase Α, lowercase α) is the first letter of the Greek alphabet. ... Beta (upper case Î’, lower case β) is the second letter of the Greek alphabet. ... Gamma (upper case Γ, lower case γ) is the 3rd letter of the Greek alphabet. ... Look up Δ, δ in Wiktionary, the free dictionary. ... Epsilon (upper case Ε, lower case ε) is the 5th letter of the Greek alphabet. ... Zeta (upper case Ζ, lower case ζ) is the sixth letter of the Greek alphabet. ... For other uses, see Eta. ... Theta (upper case Θ, lower case θ) is the 8th letter of the Greek alphabet. ... Iota (upper case Ι, lower case ι) is the 9th letter of the Greek alphabet. ... For other uses, see Kappa. ... The lambda is a unit of measure of volume (symbol λ) equal to one microlitre (1 μL) or one cubic millimetre (1 mm³). Lambda (upper case Λ, lower case λ) is the 11th letter of the Greek alphabet. ... For other uses, see Mu. ... For other uses, see Nu. ...

The Meyer-Palmen Solilunar Calendar names its months after 13 people who worked on astronomy and calendars: Aristarchus, Bruno, Copernicus, Dee, Eratosthenes, Flamsteed, Galileo, Hypatia, Ibrahim, Julius, Khayyam, Lilius and leap month Meton. The Meyer-Palmen Solilunar Calendar is a proposal for calendar reform by Peter Meyer and Karl Palmen. ... Statue of Aristarchus at Aristoteles University in Thessaloniki, Greece Aristarchus (310 BC - c. ... Giordano Bruno. ... Nicolaus Copernicus (in Latin; Polish Mikołaj Kopernik, German Nikolaus Kopernikus - February 19, 1473 – May 24, 1543) was a Polish astronomer, mathematician and economist who developed a heliocentric (Sun-centered) theory of the solar system in a form detailed enough to make it scientifically useful. ... A sixteenth century portrait of John Dee, artist unknown. ... Eratosthenes (Ἐρατοσθένης) Eratosthenes (Greek ) (276 BC - 194 BC) was a Hellenistic mathematician, geographer and astronomer. ... John Flamsteed. ... Galileo can refer to: Galileo Galilei, astronomer, philosopher, and physicist (1564 - 1642) the Galileo spacecraft, a NASA space probe that visited Jupiter and its moons the Galileo positioning system Life of Galileo, a play by Bertolt Brecht Galileo (1975) - screen adaptation of the play Life of Galileo by Bertolt Brecht... Hypatia could refer to: Hypatia of Alexandria (?370–415), a neo-Platonic philosopher, mathematician, and teacher. ... Abu Ishaq Ibrahlm ibn Habib ibn Sulaiman ibn Samura ibn Jundab al-Fazari was an 8th century Persian mathematician and astronomer at the Abbasid court of the Caliph Harun al-Rashid. ... Gāius JÅ«lius Caesar (IPA: ;[1]), July 12 or July 13, 100 BC – March 15, 44 BC) was a Roman military and political leader and one of the most influential men in world history. ... Mohammed Zahur Khayyam, better known as Khayyam is an indian music composer whose career spanned across 4 decades (1953 - 1990). ... Aloysius Lilius (Luigi Lilio, 1510 – 1576) was a physician from Calabria in Italy (at that time part of the kingdom of Naples). ... Meton of Athens was a mathematician, astronomer and engineer who lived in Athens in the 5th century BCE. He is best known for the 19-year Metonic Cycle which he introduced into the Athenian luni-solar calendar as a method of calculating dates. ...

See also

• Calculating the day of the week

This article details various mathematical algorithms to calculate the day of the week for any particular date in the past or future. ...

Specific proposals

There have been many specific calendar proposals to replace the Gregorian Calendar:

The following count one or more days outside the standard seven-day week: A week is a [ PER [unit]] of time longer than a day and shorter than a month. ...

• Positivist Calendar
• The World Calendar
• International Fixed Calendar

The following are leap week calendars: The positivist calendar was a proposal for calendar reform proposed by Auguste Comte in 1849. ... The World Calendar is a proposed reform of the Gregorian calendar created by Elisabeth Achelis of Brooklyn, New York in 1930. ... The International Fixed calendar (also known as the International Perpetual calendar, the Cotsworth plan, the Eastman plan, the 13 Month calendar or the Equal Month calendar) is a proposal for calendar reform providing for a year of 13 months of 28 days each, with one day at the end of... The leap week calendar is a reformed calendar system with a whole number of weeks every year, and with every year starting on the same weekday. ...

• Pax Calendar
• Bonavian Civil Calendar
• Common-Civil-Calendar-and-Time: C&T
• New Earth Calendar
• Symmetry454

The following simplify the months without making each year begin on the same day of the week: The Pax calendar was invented by James A. Colligan in 1930 as a reform of the Gregorian calendar. ... The Common-Civil-Calendar-and-Time calendar (C&T) is a proposal for calendar reform. ... The New Earth Calendar is a proposal for calendar reform by James A. Reich providing for a perpetual 364-day year of 13 identical months of 28 days each. ... The Symmetry454 Calendar (Sym454) is a proposal for calendar reform proposed by Dr. Irv Bromberg of the University of Toronto. ...

• Sol Calendar
• The 30x11 Calendar

The following track the moon as well as the sun: The 13-month Sol Calendar is a proposal for calendar reform by Jim Eikner of Austin, Texas, providing for a year of 13 months in length, with 12 contiguous months having 28 days each, with the final month of the year, December, having 29. ... The 30x11 (Thirty-eleven) Calendar is a calendar reform of the Gregorian calendar proposed by Stephen Abbott, a public relations consultant and writer in Manchester, New Hampshire. ...

• Hermetic Lunar Week Calendar
• The Simple Lunisolar Calendar
• Rectified Hebrew calendar
• Meyer-Palmen Solilunar Calendar

There have also been proposals to revise the way years are numbered: The Hermetic Lunar Week Calendar (HLWC) is a proposal for calendar reform by Peter Meyers. ... The Simple Lunisolar Calendar is a proposal for calendar reform by Robert Pontisso. ... The Rectified Hebrew calendar is a proposal for calendar reform by Dr. Irv Bromberg. ... The Meyer-Palmen Solilunar Calendar is a proposal for calendar reform by Peter Meyer and Karl Palmen. ...

• Holocene calendar
• Jomon Era

The Holocene calendar is a proposal for a calendar reform which aims to solve a number of problems with the current Gregorian Calendar. ... Japanese era name (年号, nengō, lit. ...

Further reading

• Steel, Duncan (2000). Marking Time: The Epic Quest to Invent the Perfect Calendar. New York: Wiley. ISBN 0-471-29827-1.

External links

• Calendar Reform by Rick McCarty
• Calendar Zone Reform Calendars
• A New Calendar - options for calendar reform
• Leap week calendars in which each year has either 364 or 371 days
• C&T calendar home page
• Slashdot discussion of Dick Henry's C&T
• The PETIN-METON Calendar
• Johns Hopkins press release on C&T
• Bob McClennon's Refomed Weekly Calendar (Leap week rule has a drafting error)
• The Symmetry454 Calendar home page
• The 30x11 Calendar home page
• Tranquility Calendar (13-month calendar)
• The 13-Moon Change movement
• The 13-Month Sol Calendar
• The New Earth Calendar (13-month calendar)
• The Synaptic Calendar (13-month calendar)
• Catholic Encyclopedia "Reform of the Calendar" Historical information