This is calconv, a program to convert between various calendars. It's my first real program, started in order to teach myself Python when I had downtime during the 2020 Covid-19 pandemic.

REQUIREMENTS

calconv is written mostly in Python 3, and uses Fortran for some of the more intense number crunching. It uses NumPy's f2py module to all Python scripts to interface with Fortran binaries, and the Tkinter toolkit to generate the GUI. Due to issues with f2py, I can't guarantee that calconv will run properly on Microsoft Windows.

The specific programs you will need to compile and run calconv are:

A Python 3 interpreter. This comes as standard with Linux, BSD, and I believe Mac.
The NumPy library. The Anaconda Python distribution comes with NumPy built in.
The Tkinter library
A Fortran compiler. The standard Fortran compiler on Unix-like operating systems is gfortran; on Windows, ifort is more common, but my Fortran makes use of features which ifort might not include

All these components should be available through your package manager (called an "app store" on Mac and Windows). If you do not wish to use a graphical program to install everything, you can enter the following commands on the command line in Linux:

Arch (Chakra, Manjaro):

$ sudo pacman -Syu python tk python-numpy gcc-fortran

Debian (Ubuntu, Mint):

$ sudo apt-get install python3 python3-tk python3-numpy gfortran

Fedora (CentOS, Red Hat Enterprise Linux, PCLinuxOS):

$ sudo dnf install python3 python3-tk python3-numpy gcc-gfortran

MS Windows users can download the components from the following links:

Python (including NumPy and Tk): https://www.anaconda.com/products/individual
gfortran: http://www.equation.com/servlet/equation.cmd?fa=fortran

COMPILING

Before you can run calconv, you will need to compile the Fortran code. In the command line, navigate to the folder where you unpacked the source code (which should be the one containing this Readme file) and type the following:

f2py -c sunmoon.f90 -m sunmoon
f2py -c zodiac.f90 -m zodiac
f2py -c tibetan.f90 -m tibetan

(This only needs to be done once; however, if Python is updated to a new version number, it can break compatibility with binary code, and so a recompile will be necessary)

RUNNING

From the command line, navigate to the folder where you unpacked the program and type:

./calconv.py

On Windows, you can instead double-click on calconv.bat

Dates are entered in the indicated text boxes in the order Day, Month, Year; if there is only one text box, input is a simple number. For now, months must be written in full, and entered exactly as listed here, including punctuation and diacritical marks. A later version will replace the text entry fields with selectable dropdown menus. Years before the calendar epoch are entered as negative numbers; so, for example, the year 44 BC would be input as '-44'.

Julian calendars, Gregorian calendars, Parker, Goucher-Parker, Serbian Church, World, International Fixed, Pax, Gorman, Georgian (Christian era), ADA, and Holocene Calendars:

January
February
Gormanuary (Gorman calendar only)
Intermission (Gorman calendar only)
March
April
May
June
Sol (International Fixed calendar only)
July
August
September
October
November
Pax (Pax calendar only)
December
Worldsday (World calendar only)
Year Day (International Fixed calendar only)
Leap day (World and International Fixed calendars only)
Georgy (Georgian calendar only)
Christmas (Georgian calendar only)
Olympiad (Georgian calendar only)

Ethiopian Calendar:

Mäskäräm
Ṭəqəmt
Ḫədar
Taḫśaś
Ṭərr
Yäkatit
Mägabit
Miyazya
Gənbo
Säne
Ḥamle
Nähase
Ṗagume
Extra Days

Coptic Calendar:

Thout
Paopi
Hathor
Koiak
Tobi
Meshir
Paremhat
Parmouti
Pashons
Paoni
Epip
Mesori
Extra days

Egyptian and Sothic Calendars:

Thoth
Phaophi
Hathor
Choak
Tybi
Mechir
Phamenoth
Pharmuthi
Pachons
Payni
Spiphi
Mesore
Extra days

Lunar Hijri, Tabular Islamic, and Pre-Islamic Arab calendars:

Muharram
Safar
Rabi' al-awwal
Rabi' al-Thani
Jumada al-awwal
Jumada al-Thani
Rajab
Sha'ban
Ramadan
Shawwal
Dhu al-Qidah
Dhu al-Hijjah
Nasiʾ (Pre-Islamic Arab calendar only)

Jalali, Solar Hijri, Ahmad Birashk's, Iranian National, Qadimi, Shenshai, Oshmurtik, Vihezakik, Shahanshahi, Fasli, Young Avestan Calendars:

Farvardin
Ordibehesht
Khordad
Tir
Mordad
Shahrivar
Mehr
Aban
Azar
Dey
Bahman
Esfand
Kabizeh (Young Avestan, Shahanshahi, and Vihezakik calendars only)

Armenian Calendar:

Nawasard
Hoṙi
Sahmi
Trē
Kʿałocʿ
Arac
Mehekan
Areg
Ahekan
Mareri
Margac
Hrotic'
Extra days

Modern Assyrian Calendar

Nīsān
ʾĪyār
Ḥzīrān
Tammūz
Ṭabbāḥ
ʾĪlūl
Tešrīn Qḏīm
Tešrīn Ḥrāy
Kānōn Qḏīm
Kānōn Ḥrāy
Šḇāṭ
Āḏar

Babylonian Calendars:

Nisānu
Āru
Simanu
Dumuzu
Abu
Ulūlu
Ulūlu Arku (only in the 17th year of the Metonic cycle)
Tišritum
Samnu
Kislimu
Ṭebētum
Šabaṭu
Addaru
Addaru Arku (leap years only)

Hebrew (Jewish and Samaritan) calendars:

Tishrei
Marcheshvan
Kislev
Tevet
Shevat
Adar
Veadar (leap years only)
Nisan
Iyar
Sivan
Tammuz
Av
Elul

(Note: Everyone else lists Nisan as the first month of the year, and Adar/Veadar as the last. This is for Jewish cultural reasons; however, Tishrei is the first month of the civil Hebrew calendar, as it is on 1 Tishrei that the year number increments. I have listed the months in this order to avoid confusion. Nisan is the first month of the year in the Samaritan and Karaite calendars).

Kurdish calendar:

Jejhnan
Gullan
Zerdan
Púshperr
Gelawéjh
Xermanan
Beran
Xezan
Saran
Befran
Rébandan
Reshemé

Amazigh calendar:

Yennayer
Yebrayer
Mares
Yebrir
May
Yunyu
Yulyuz
Ɣuct
Shutembir
Ktuber
Nwambir
Dujembir

Rumi (Ottoman fiscal) calendar:

Mart
Nisan
Mayıs
Haziran
Temmuz
Ağustos
Eylül
Teşrin-i Evvel
Teşrin-i Sânî
Kânûn-ı Evve
Kânûn-ı Sânî
Şubat

Pax 2020:

Initium
Rutilante
Semen
Gaudium
Apes
Serenium
Coleum
Amare
Messis
Follium
Nixcumumis
Pax
Requiem

Positivist calendar

Moses
Homer
Aristotle
Archimedes
Caesar
St. Paul
Charlemagne
Dante
Gutenberg
Shakespeare
Descartes
Frederick II
Bichat
Festival of All the Dead
Festival of Holy Women

French Republican calendars:

Vendémiaire
Brumaire
Frimaire
Nivôse
Pluviôse
Ventôse
Germinal
Floréal
Prairial
Messidor
Thermidor
Fructidor
Sans-culottides

Thellid calendar

Alvakku
Bethanis
Duvadda
Emovvi
Forkithal
Kalvazzi
Irentos
Jukennuk
Miskullen
Ossakov
Raikkaved
Underro
Zithebbe
Leap Day (leap years only)
Old Year's Day

Igbo calendar

Mbụ
Abụo
Ife Eke
Anọ
Agwụ
Ifejiọkụ
Alọm Chi
Ilo Mmụọ
Ana
Okike
Ajana
Ede Ajana
Ụzọ Alụsị

Roman calendar

Martius
Aprilis
Maia
Iunius
Quintilis
Sextilis
Septembris
Octobris
Novembris
Decembris
Ianuarius
Februarius

Macedonian and Seleucid calendars:

Dios
Apellaiios
Audunaios
Peritios
Dystros
Xanthikos
Xandikos Embolimos (leap years only)
Artemisios
Daisios
Panamos
Lōios
Gorpiaios
Hyperberetaios
Hyperberetaios Embolimos (only in some leap years)

Georgian calendar (Georgian Era)

Peter
Andrew
James the Great
John
Philip
Bartholomew
Thomas
Matthew
James the Less
Jude
Simon
Matthias
Paul

Korean:

Il-wol
I-wol
Sam-wol
Sa-wol
O-wol
Yu-wol
Chil-wol
Pal-wol
Gu-wol
Si-wol
Sibil-wol
Sibi-wol

To get the leap month, add "Yun " before the name of the month.

Inca:

Intiraymipacha
Pachacyahuarllamapacha
Yapuypacha
Coyaraymipacha
Paramañaypacha
Ayamarcaypacha
Capacintiraymipacha
Huacapacha
Huarachicuypacha
Paraypacha
Rinrituccinapacha
Aymuraypacha
Intihuatapacyapanapacha (leap years only in the civil calendar)

Chinese lunisolar calendars:

Zhēngyuè
Èryuè
Sānyuè
Sìyuè
Wǔyuè
Liùyuè
Qīyuè
Bāyuè
Jiǔyuè
Shíyuè
Shíyīyuè
Làyuè

To get the leap month in the Chinese lunisolar calendar, precede it with "Rùn", for example "Rùn Zhēngyuè". In the Chinese lunisolar calendar, the leap month can occur anywhere in the year. For this reason, if a leap month is specified in a non-leap year, the algorithm assumes the user means the corresponding regular month; conversely, if an incorrect leap month is specified in a leap year, the algorithm assumes that the user means the actual leap month.

Chinese solar calendars:

Lìchūn
Yǔshuı̌
Jı̄ngzhé
Chūnfēn
Qı̄ngmíng
Gǔyǔ
Lìxià
Xiǎomǎn
Mángzhòng
Xiàzhì
Xiǎoshǔ
Dàshǔ
Lìqiū
Chǔshǔ
Báilù
Qiūfēn
Hánlù
Shuāngjiàng
Lìdōng
Xiǎoxuě
Dàxuě
Dōngzhì
Xiǎohán
Dàhán

Older Chinese calendars:

Dōngyuè
Bīngyuè
Zōuyuè
Xìngyuè
Táoyuè
Méiyuè
Liúyuè
Héyuè
Lányuè
Guìyuè
Júyuè
Lùyuè
Rùnyuè (leap years only)

Vietnamese calendar:

Tháng Giêng
Tháng Hai
Tháng Ba
Tháng Tư
Tháng Năm
Tháng Sáu
Tháng Bảy
Tháng Tám
Tháng Chín
Tháng Mười
Tháng Mười Một
Tháng Chạp
Tháng Nhuận (leap years only)

Japanese calendars:

Ichigatsu
Nigatsu
Sangatsu
Shigatsu
Gogatsu
Rokugatsu
Shichigatsu
Hachigatsu
Kugatsu
Juugatsu
Juuichigatsu
Juunigatsu
Uruzuki (lunisolar calendar, leap years only)

Mongolian traditional calendar:

Negdugeer sar
Khoyordugaar sar
Guravdugaar sar
Dörövdugeer sar
Tarvdugaar sar
Zurgadugaar sar
Doldugaar sar
Naĭmdugaar sar
Yesdugeer sar
Aravdugaar sar
Arvannegdugeer sar
Arvanchaërdugaar sar

To get the leap month, prefix the month name with "Shün ", such as "Shün Negdugeer sar"

Bahá'í calendars:

Bahá
Jalál
Jamál
ʻAẓamat
Núr
Raḥmat
Kalimát
Kamál
Asmáʼ
ʻIzzat
Mas͟híyyat
ʻIlm
Qudrat
Qawl
Masáʼil
S͟haraf
Sulṭán
Mulk
Ayyám-ul Há
ʻAláʼ

Old Avestan calendars:

Ādukanaisha
Thūravāhara
Thāigracish
Garmapada
Thurnabadish
Garbashiyash
Bāgayādish
Vrkazana
Āçiyādiya
Anāmaka
Thwayauvā
Vixayana
Kabizeh (leap years only)
Kabizeh 2 (double leap years only)

Sogdian calendar:

Nausardh
Xorezhnic
Nisanic
Pusākic
Shnāk-Xandic
Xazānānc
Baghakānic
Āpānc
Bōghic
Mushboghic
Zhimdic
Xshūmic
Extra days

Indian solar calendars:

Meṣa
Vṛṣabha
Mithuna
Karkaṭa
Siṃha
Kanyā
Tulā
Vṛścika
Dhanu
Makara
Kumbha
Mīna

(Note: In the Keralite/Malayam calendars, Siṃha is the first month)

Indian lunisolar calendars:

Chaitra
Vaisākha
Jyēshtha
Āshādha
Shrāvana
Bhādra
Āshwin
Kārtika
Agrahāyana
Pausha
Māgha
Phālguna
Adhikmasa (Vedāṅga Jyotiṣa only)

(Note: In some calendars, Vaisākha is the first month). To specify a leap month in a lunisolar calendar, prefix the month name with "Adhik ".

Malayam calendar (Uthara Malayala Panchangam):

Kanni
Thulam
Vrischikam
Dhanu
Makaram
Kumbham
Meenam
Medam
Edavam
Midhunam
Karkitaka
Chingam

Tamil calendar:

Chittirai
Vaikāsi
Āni
Ādi
Āvani
Purattāsi
Aippasi
Kartikai
Mārgazhi
Thai
Māsi
Panguni

Bengali calendars:

Bôishakh
Jyôishțhô
Āshāḍh
Srabôn
Bhadrô
Aśvin
Kartik
Ôgrôhayôn
Poush
Magh
Falgun
Chôitrô

Assamese calendar:

Böhag
Zeth
Ahar
Xaün
Bhado
Ahin
Kati
Aghün
Puh
Magh
Fagun
Söt

Odia calendar:

Baiśākha
Jyeṣṭha
Āṣāḍha
Śrābaṇa
Bhādraba
Āświna
Kārttika
Mārgaśira
Pauṣa
Māgha
Phālguna
Caitra

Manipuri calendar:

Sajibhu
Kalen
Inga
Ingel
Thawan
Langban
Mera
Hiyangei
Poineu
Wakching
Phairen
Lamda

Mandaean calendar:

Daula
Nuna
'mbra
Taura
Ṣilmia
Sarṭana
Aria
Shumbulta
Extra days
Qaina
Arqba
Hiṭia
Gadia

Nanakshahi calendars:

Chet
Vaisakh
Jeth
Harh
Sawan
Bhadon
Asu
Kartik
Maghar
Poh
Magh
Phagun

Nepali calendars:

Kachhalā
Thinlā
Pwanhelā
Silā
Chilā
Chaulā
Bachhalā
Tachhalā
Dilā
Gunlā
Tanlā
Kaulā
Analā (leap years in the lunisolar calendar only)

Tibetan and Bhutanese calendars:

Mchu
Dbo
Nag pa
Sa ga
Snron
Chu stod
Gro Bzhin
Khrums
Tha skar
Smin drug
Mgo
Rgyal

To specify a leap month, put "Leap " before the month name

Myanmar calendars:

Tagu
Kason
Nayon
Wahso
Wahgaung
Tawthalin
Thadinkyut
Tazaungmon
Natdaw
Pyatho
Tabodwe
Tabaung

Leap months are indicated by adding " 2" to the end of Wahso (or Tagu in the case of the Arakan calendar). If it's a date in Tagu before solar new year, add an "*" to the year number to indicate that the lunar year has begun but the year number has not yet incremented. The Kayin calendar year begins on 1 Pyatho, and not on solar near year.

Thai sidereal calendars:

Meesaă
Phrɯ́tsaphaa
Míthùnaa
Kàrákàdaa
Sǐnghǎa
Kanyaa
Tùlaa
Phrɯ́tsacìkaa
Thanwaa
Mákàraa
Kumphaa
Miinaa

Thai tropical calendars:

Mákàraa-khom
Kumphaa-phan
Miinaa-khom
Meesaǎ-yon
Phrɯ́tsaphaa-khom
Míthùnaa-yon
Kàrákàdaa-khom
Sǐnghǎa-khom
Kanyaa-yon
Tùlaa-khom
Phrɯ́tsacìkaa-yon
Thanwaa-khom

Thai lunisolar calendars:

Deuan hâa
Deuan hòk
Deuan jèt
Deuan bpàaet
Deuan gâo
Deuan sip
Deuan sip nùeng
Deuan sip sǎawng
Deuan aai
Deuan yi
Deuan sǎam
Deuan sì

Thai months are a bit weird. Deuan aai means "Month the first", but the year doesn't increment until Songkran, or solar new year, which falls several months afterward. The lunar month containing solar year year is called Deuan hâa in Laos and Central Thailand, Deuan hòk in Keng Tung, and Deuan jèt in Chiang Mai; note that these are the same month and all correspond to the Indian Chaitra, it's just that the month called "Month 5" in Central Thailand is called "Month 6" in Keng Tung and "Month 7" in Chiang Mai.

The leap month always follows the 5th month of lunar year; it is formed by appending " song khan" to the end. Thus, it is called Deuan bpàaet song khan in Central Thailand and Laos, Deuan gào song khan in Keng Tung, and Deuan sip song khan in Chiang Mai.

To specify that a date comes on or after lunar new year but before solar new year, add an '*' to the year to specify that the year number has yet to increment.

Cambodian months:

Chaet
Vesak
Jais
Ashad (technically not in leap years)
Bhadamasad (replaces Ashad in leap years)
Thutiyasad (leap month)
Srap
Phutrobot
Asuj
Kadhek
Mekasay
Bos
Meak
Phagaun

Balinese calendars:

Mangsa Kasadasa
Mangsa Desta
Mangsa Saddha
Mangsa Kasa
Mangsa Karo
Mangsa Katelu
Mangsa Kapat
Mangsa Kalima
Mangsa Kanem
Mangsa Kapitu
Mangsa Kawolu
Mangsa Kasanga

In the case of leap years, add a " 2" to the end of the repeated month.

Javanese calendars:

Sura
Sapar
Mulud
Bakda Mulud
Jumadil Awal
Jumadil Akhir
Rejeb
Ruwah
Pasa
Sawa
Dulkangidah
Besar

LICENSE

calconv is copyright Chris McCrohan.

calconv is licensed under the GNU General Public License version 3.0 or, at your option, any later version. Full details are contained in the LICENSE file. In short, you are free to alter, copy, and redistribute this software (and even charge a fee for it) as you please, and anybody who received a copy from you has the same rights.

FUTURE GOALS

Replace the text boxes for months with dropdown menus.

Add the following calendars:

Byzantine
Shire Reckoning
ISO
Discordian
Minguo
Julian Period
Muisca
Mandean (Reingold and Dershowitz, p 129)
Pawukon
Akan