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.

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

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:

f2py3 -c sunmoon.f90 -m sunmoon
f2py3 -c zodiac.f90 -m zodiac

(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)

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'.

• 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)

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

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

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

• 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)

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

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

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

• 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)

• 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).

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

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

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

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

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

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

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

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

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

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

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

• 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.

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

• 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.

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

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

• 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)

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

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

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

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

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

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

• 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 ".

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

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

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

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

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

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

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

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

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

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.

Replace the text boxes for months with dropdown menus.

Add the following calendars:

• Byzantine
• Shire Reckoning
• Buddhist
• Indian
• ISO
• Saka
• Bengali
• Myanmar
• Discordian
• Vikram Samvat
• Shaka Samvat
• Kali Yuga
• Javanese
• Minguo
• Nanakshahi
• Thai
• Tibetan
• Julian Period
• Muisca
• Mandean (Reingold and Dershowitz, p 129)
• Pawukon
• Akan