Hindu units of time
Hindu texts describe units of Kala measurements, from microseconds to Trillions of years.^{[1]} According to these texts, time is cyclic, which repeats itself forever.^{[2]}
Contents
Time units
Various units of time are used across the Vedas, Bhagavata Purana, Vishnu Puran, Mahabharata, Suryasidhanta etc.A summary of the Hindu metrics of time (kāla vyavahāra) follows.^{[3]}
Sidereal metrics
Unit  Definition  Relation to SI units  

Truti  त्रुति  Base unit  ≈ 0.031 µs 
Renu  रेणु  60 Truti  ≈ 1.86 µs 
Lava  लव  60 Renu  ≈ 0.11 ms 
Līkṣaka  लीक्षक  60 Lava  ≈ 6.696 ms 
Lipta  लिप्ता  60 Leekshaka  ≈ 0.401 s 
Vipala  विपल  
Pala  पल  60 Lipta  ≈ 24.1056 s 
Vighaṭi  विघटि  
Vinādī  विनाडी  
Ghaṭi  घटि  60 Vighaṭi  ≈ 24 min 
Nādī  नाडी  
Danda  दण्ड  
Muhūrta  मुहूर्त  2 Ghaṭi  ≈ 48 min 
Nakṣatra Ahorātram (Sidereal Day)  नक्षत्र अहोरात्रम्  60 Ghaṭī  ≈ 24 h 
30 Muhūrta  ≈ 24 h 
Unit  Definition  Relation to SI units 

Truti  Base unit  ≈ 35.5 µs 
Tatpara  100 Truti  ≈ 3.55 ms 
Nimesha  30 Tatpara  ≈ 106.7 ms 
Kāṣṭhā  30 Nimesha  ≈ 3.2 s 
Kalā  30 Kāṣṭhā  ≈ 1.6 min 
Muhūrta  30 Kalā  ≈ 48 min 
Nakṣatra Ahorātram (Sidereal Day)  30 Muhūrta  ≈ 24 h 
Small units of time used in the Vedas
Unit  Definition  Relation to SI units 

Paramāṇu  Base unit  ≈ 26.3 µs 
Aṇu  2 Paramāṇu  ≈ 52.67 µs 
Trasareṇu  3 Aṇu  ≈ 158 µs 
Truṭi  3 Trasareṇu  ≈ 474 µs 
Vedha  100 Truṭi  ≈ 47.4 ms 
Lava  3 Vedha  ≈ 0.14 s 
Nimeṣa  3 Lava  ≈ 0.43 s 
Kṣaṇa  3 Nimesha  ≈ 1.28 s 
Kāṣṭhā  5 Kṣaṇa  ≈ 6.4 s 
Laghu  15 Kāṣṭhā  ≈ 1.6 min 
Danda  15 Laghu  ≈ 24 min 
Muhūrta  2 Danda  ≈ 48 min 
Ahorātram (Day)  30 Muhūrta  ≈ 24 h 
Masa (Month)  30 Ahorātram  ≈ 30 days 
Ritu (Season)  2 Masa  ≈ 2 months 
Ayana  3 Ritu  ≈ 6 months 
Samvatsara (Year)  2 Ayana  ≈ 365 days^{[4]} 
Ahorātram of Deva 
Lunar metrics
 A Tithi or lunar day is defined as the time it takes for the longitudinal angle between the moon and the Sun to increase by 12°.Tithis begin at varying times of day and vary in duration from approximately 19 to approximately 26 hours.^{[5]}^{[6]}
 A Paksa (also Pakṣa) or lunar fortnight consists of 15 tithes.^{[5]}
 A Māsa or lunar month (approximately 29.5 days) is divided into 2 Pakṣas: the one between new moon and full moon (waxing) is called gaura or (bright) or Śukla Pakṣa; the one between full moon and new moon (waning) Kṛiṣhṇa (dark) paksha^{[5]}
 A Ṛitu (or season) is 2 Māsa^{[5]}
 An Ayana is 3 Ṛitus^{[5]}
 A year is two Ayanas^{[5]}
Tropical metrics
 A Yāma = 1/4 of a day (light) or night [ = 7½ Gratis (घटि) = 3¾ Muhurtas = 3 Horas (होरा) ]
 Eight Yāmas make half of the day (either day or night)
 An Ahorātra is a tropical day (Note: A day is considered to begin and end at sunrise, not midnight.)^{[7]}
Name  Definition  Equivalence  

Yama  याम  ¼th of a day (light) or night  ≈ 3 hours 
Sāvana Ahorātram  सावन अहोरात्रम्  8 Yamas  1 Solar day 
Reckoning of time among other entities
Among the Pitṛs (forefathers)
 1 day of pitras = 1 solar masa (month)
 30 days of pitras = 1 month of pitras
 12 months of pitras = 1 year of pitras
The Lifespan of the pitras is 100 years of pitras (3,000 Solar years).^{[7]}
Among the Devas
The life span of any Hindu deva spans nearly (or more than) 4.5 million years. Statistically, we can also look it as:
 12000 Deva Years = Life Span of Devas = 1 MahāYuga.^{[8]}
The Viṣṇu Purāṇa Time measurement section of the Viṣṇu Purāṇa Book I Chapter III explains the above as follows:
 2 Ayanas (6month periods, see above) = 1 human year or 1 day of the devas
 4,000 + 400 + 400 = 4,800 divine years (= 1,728,000 human years) = 1 Satya Yuga^{[8]}
 3,000 + 300 + 300 = 3,600 divine years (= 1,296,000 human years) = 1 Treta Yuga^{[8]}
 2,000 + 200 + 200 = 2,400 divine years (= 864,000 human years) = 1 Dvapara Yuga^{[8]}
 1,000 + 100 + 100 = 1,200 divine years (= 432,000 human years) = 1 Kali Yuga^{[8]}
 12,000 divine year = 4 Yugas (= 4,320,000 human years) = 1 MahāYuga (also is equaled to 12000 Daiva (divine) Yuga)^{[8]}
 [2*12,000 = 24,000 divine year = 12000 revolutions of sun around its dual]^{[8]}
For Brahma
 1000 MahāYugas = 1 Kalpa = 1 day (day only) of Brahma
(2 Kalpas constitute a day and night of Brahma, 8.64 billion human years)
 30 days of Brahma = 1 month of Brahma (259.2 billion human years)
 12 months of Brahma = 1 year of Brahma (3.1104 trillion human years)
 50 years of Brahma = 1 Parārdha (156,764,160,000,000 human years)
 2 parardhas = 100 years of Brahma = 1 Para = 1 MahāKalpa (the lifespan of Brahma) (313,528,320,000,000 human years)
One day of Brahma is divided into 1000 parts called charaṇas.^{[9]}
Four Yugas
Yugas can be understood easily by the Set theory. Satya Yuga is the largest set & other yugas are its subsets. It also implies that Satya/Truth exists in all Yugas. The charaṇas are divided as follows:
4 charaṇas (1,728,000 solar years)  Satya Yuga 
3 charaṇas (1,296,000 solar years)  Treta Yuga 
2 charaṇas (864,000 solar years)  Dvapara Yuga 
1 charaṇas (432,000 solar years)  Kali Yuga 
Source: [1] 
The cycle repeats itself, so altogether there are 1,000 cycles of MahāYuga in one day of Brahma.

 One cycle of the above four Yugas is one MahāYuga (4.32 million solar years)
 as is confirmed by the Gītā Śloka 8.17 (statement) "sahasrayugaparyantam ahar yad brahmaṇo viduḥ rātriṁ yugasahasrāntāṁ te 'horātravido janāḥ", meaning, a day of brahma is of 1000 MahāYuga. Thus a day of Brahma, Kalpa, is of duration: 4.32 billion solar years. Two Kalpas constitute a day and night (Adhi Sandhi) of Brahma.^{[10]}
 A Manvantara consists of 71 MahāYuga (306,720,000 solar years). Each Manvantara is ruled by a Manu.^{[11]}
 After each Manvantara follows one Saṃdhi Kāla of the same duration as a Kṛta Yuga (1,728,000 = 4 Charaṇas). (It is said that during a Saṃdhi Kāla, the entire earth is submerged in water.)^{[11]}
 A Kalpa consists of a period of 4.32 Billion solar years followed by 14 Manvataras and Saṃdhi Kalas.^{[11]}
 A day of Brahma equals
 (14 times 71 MahāYuga) + (15 × 4 Charaṇas)
 = 994 MahāYuga + (15 * 4800)
 = 994 MahāYuga + (72,000 years)[deva years] / 6 = 12,000[deva years] viz. one maha yuga.
 = 994 MahāYuga + 6 MahāYuga
 = 1,000 MahāYuga.^{[9]}
Current Date
Currently, 50 years of Brahma have elapsed. The last Kalpa at the end of 50th year is called Padma Kalpa. We are currently in the first 'day' of the 51st year.^{[12]} This Brahma's day, Kalpa, is named as ShvetaVaraha Kalpa. Within this Day, six Manvantaras have already elapsed^{[13]} and this is the seventh Manvantara, named as – Vaivasvatha Manvantara (or Sraddhadeva Manvantara). Within the Vaivasvatha Manvantara, 27 Mahayugas^{[13]} (4 Yugas together is a Mahayuga), and the Krita,^{[14]} Treta and Dwapara Yugas of the 28th Mahayuga have elapsed. This Kaliyuga is in the 28th Mahayuga. This Kaliyuga began in the year 3102 BCE in the proleptic Julian Calendar.^{[15]} Since 50 years of Brahma have already elapsed, this is the second Parardha, also called as Dvithiya Parardha.
Calculating the elapsed time since current Brahma's creation
432000 × 10 × 1000 × 2 = 8.64 billion years (2 Kalpa (day and night))
8.64 × 10^{9} × 30 × 12 = 3.1104 Trillion Years (1 year of Brahma)
3.1104 × 10^{12} × 50 = 155.52 trillion years (50 years of Brahma)
(6 × 71 × 4320000) + 7 × 1.728 × 10^6 = 1852416000 years elapsed in first six Manvataras, and Sandhi Kalas in the current Kalpa
27 × 4320000 = 116640000 years elapsed in first 27 Mahayugas of the current Manvantara
1.728 × 10^6 + 1.296 × 10^6 + 864000 = 3888000 years elapsed in current Mahayuga
3102 + 2017 = 5119 years elapsed in current Kaliyuga.
So the total time elapsed since current Brahma is
155520000000000 + 1852416000 + 116640000 + 3888000 + 5119 = 155,521,972,949,119 years
(one hundred fiftyfive trillion, five hundred twentyone billion, nine hundred seventytwo million, nine hundred fortynine thousand, one hundred nineteen years) as of 2018 AD
Total age of Brahma is 100 (Brahma Years) which is equal to 313,528,320,000,000 Human years
The current Kali Yuga began at midnight 17 February / 18 February in 3102 BCE in the proleptic Julian calendar.^{[16]} As per the information above about Yuga periods, only 5,119 years are passed out of 432,000 years of current Kali Yuga, and hence another 426,881 years are left to complete this 28th Kali Yuga of Vaivaswatha Manvantara.^{[note 1]}
See also
 Age of the universe
 Cosmology
 Hindu astronomy
 Hindu calendar
 Indian mathematics
 Indian science and technology
 Indian weights and measures
 Jyotish
 List of numbers in Hindu scriptures
 Universe
 Vedanga Jyotisha
 Vedas
 Yojana
Notes
 ^ According to Sri Yukteswar Giri, guru of Paramahansa Yogananda, The ascending phase of the Kali Yuga began in September 499 CE. Since September 1699, we have been in the ascending phase of the Dwapara Yuga. According to Sri Yukteswar, nobody wanted to announce the bad news of the beginning of the descending Kali Yuga, so they kept adding years to the Dvapara date (at that time 2400 Dvapara) only retitling the epoch to Kali.^{[17]}
References
 ^ S.V. Gupta. Units of Measurement: Past, Present and Future. International System of Units. Springer. p. 3.
 ^ Dick Teresi. Lost Discoveries: The Ancient Roots of Modern Sciencefrom the Baby. SimonandSchuster. p. 174.
 ^ S.V. Gupta. Units of Measurement: Past, Present and Future. International System of Units. Springer. p. 4,5.
 ^ S.V. Gupta. Units of Measurement: Past, Present and Future. International System of Units. Springer. p. 5.
 ^ ^{a} ^{b} ^{c} ^{d} ^{e} ^{f} S.V. Gupta. Units of Measurement: Past, Present and Future. International System of Units. Springer. p. 5,6.
 ^ Kumar, Ashwini (2005). Vaastu: The Art And Science Of Living. Sterling Publishers Pvt. Ltd. p. 50. ISBN 8120725697.
 ^ ^{a} ^{b} S.V. Gupta. Units of Measurement: Past, Present and Future. International System of Units. Springer. p. 6.
 ^ ^{a} ^{b} ^{c} ^{d} ^{e} ^{f} ^{g} Hans Kng. Tracing The Way: Spiritual Dimensions of the World Religions. A&C Black. p. 50.
 ^ ^{a} ^{b} Bryan E. Penprase. The Power of Stars. Springer. p. 182.
 ^ Swami Mukundananda. Bhagavad Gita The Song of God.
 ^ ^{a} ^{b} ^{c} Bryan E. Penprase. The Power of Stars. Springer. p. 182.
 ^ Burgess, Chapter 1, Verse 21
 ^ ^{a} ^{b} Burgess, Chapter 1, Verse 22
 ^ Burgess, Chapter 1, Verse 23
 ^ Burgess, p17
 ^ Burgess, Ebenezer Translation of the SûryaSiddhânta: A textbook of Hindu astronomy, with notes and an appendix Originally published: Journal of the American Oriental Society 6 (1860) 141–498 , p17"
 ^ Yukteswar 1949.
 Victor J. Katz. A History of Mathematics: An Introduction, 1998.
External links
 Translation of the Surya Siddhanta (1861)
 Daily Hindu Calendar
 Exegesis of Hindu Cosmological Time Cycles
 Surya Siddhanta, Chapter I with Commentary and Illustrations
 Vedic Time Converter