The Tibetan Calendar
A living astronomical tradition spanning over a millennium
Bridging the celestial movements with daily life and spiritual practice
Today in the Tibetan Calendar
An Ancient Science for Modern Times
The Tibetan calendar (བོད་ཀྱི་ལོ་ཐོ།) is far more than a system for marking days. It is a sophisticated astronomical and astrological framework derived from the Kālacakra Tantra, encoding centuries of observation, mathematical refinement, and spiritual insight.
Unlike the purely solar Gregorian calendar, the Tibetan system is lunisolar—tracking both the Moon's phases and the Sun's annual journey. Each day carries multiple layers of meaning: the lunar mansion, the yoga, the karana, elemental combinations, and auspicious or inauspicious qualities that inform everything from agriculture to meditation practice.
This project makes these calculations accessible through interactive tools and comprehensive educational content, preserving and sharing this remarkable tradition.
Explore the System
Discover the interconnected elements of Tibetan timekeeping through our interactive tools and educational resources.
Date Calculator
Convert between Tibetan and Western dates. See lunar days, mansions, yogas, karanas, and elemental qualities for any date.
Months & Years
Understand the 60-year cycle, animal-element combinations, intercalary months, and how years are named and counted.
Days & Time
Learn about lunar days (tshes pa), duplicated and skipped days, and the Tibetan divisions of time.
Astrology
Explore lunar mansions (rgyu skar), yogas (sbyor ba), karanas (byed pa), and how they influence daily activities.
Technical Details
Dive into the mathematics: mean and true longitudes, anomaly corrections, epoch calculations, and more.
About TCG
Learn about Edward Henning's Tibetan Calendar Generator and how this web application was built from his C code.
Five Calculation Traditions
Tibetan astronomy developed several distinct calculation traditions, each refining the parameters to improve accuracy. This application supports all five major systems implemented in Henning's TCG software.
Phugpa (ཕུག་པ་)
Epoch: -1000 CE
The most widely used system, standardized by Phugpa Lhundrup Gyatso. This is the default tradition used by the major Tibetan Buddhist schools and the Tibetan government-in-exile.
Tsurphu (མཚུར་ཕུ་)
Epoch: -1000 CE
Developed at Tsurphu Monastery, seat of the Karmapas. Used primarily by the Karma Kagyu school. Features slightly different parameters resulting in occasional day differences from Phugpa.
Error Correction (འཁྲུལ་སེལ་)
Epoch: -2000 CE
A refined system attempting to correct accumulated errors. Uses an earlier epoch for greater precision over long time spans.
mkhas pa'i snying nor
Epoch: 1796 CE
"Essence of the Wise" — a scholarly tradition documented in the 18th century with a much more recent epoch date.
New Ganden (དགེ་ལྡན་རྩིས་གསར་)
Epoch: 1747 CE
Modern calculations from the Gelug tradition, refined at Ganden Monastery with updated astronomical parameters.
Begin Your Exploration
Whether you're a practitioner, scholar, or curious learner, discover the depth and beauty of Tibetan timekeeping.