Hindu units of time

Hindu units of time are described in Hindu texts ranging from microseconds to trillions of years, including cycles of cosmic time that repeat general events in Hindu cosmology. Time () is described as eternal.Template:Sfn Various fragments of time are described in the Vedas, Manusmriti, Bhagavata Purana, Vishnu Purana, Mahabharata, Surya Siddhanta etc.

Sidereal metrics

File:HinduMeasurements.svg

Hindu measurements in logarithmic scale based on seconds

Sidereal astrology maintains the alignment between signs and constellations via corrective systems of Hindu (Vedic)-origin known as ayanamsas (Sanskrit: 'ayana' "movement" + 'aṃśa' "component"), to allow for the observed precession of equinoxes, whereas tropical astrology ignores precession. This has caused the two systems, which were aligned around 2,000 years ago, to drift apart over the centuries.

Ayanamsa systems used in Hindu astrology (also known as Vedic astrology) include the Lahiriayanamsa and the Raman ayanamsa. The Fagan-Bradley ayanamsa is an example of an ayanamsa system used in Western sidereal astrology. As of 2020, zodiacal signs calculated using the Sri Yukteswar ayanamsa were around 23 degrees behind tropical zodiacal signs. Per these calculations, persons born between March 12 - April 12, for instance, would have the sun sign of Pisces. By contrast, persons born between March 21 - April 19 would have the sun sign of Aries per tropical calculations.

Sidereal Units:Template:Sfn

Unit	Definition	Value in SI units
truti ()	base unit	≈ 308.6 ns
reṇu ()	60 truti	≈ 18.5 μs
lava ()	60 renu	≈ 1,111 μs
()	60 lava	≈ 66.66 ms
()	6	≈ 0.4 s
vipala ()
()	10	≈ 4 s
pala ()	60 or 6	≈ 24 s
()
()
()	60	≈ 1.44 ks (24 min)
()
daṇḍa ()
()	2	≈ 2.88 ks (48 min)
(sidereal day; )	60	≈ 86.4 ks (24 h)
	30

According to :Template:Sfn

Unit	Definition	Value in SI units
truti	base unit	≈ 29.6 μs
tatpara	100 truti	≈ 2.96 ms
nimesha	30 tatpara	≈ 88.9 ms
	18 nimesha	≈ 1.6 s
	30	≈ 48 s
ghatika	30	≈ 1.44 ks (24 min)
()	2 ghatika	≈ 2.88 ks (48 min)
(sidereal day)	30	≈ 86.4 ks (24 h)

Small units of time used in the Vedas:Template:Sfn

Unit	Definition	Value in SI units
	base unit	≈ 26.3 μs
	2	≈ 52.67 μs
	3	≈ 158 μs
	3	≈ 474 μs
vedha	100	≈ 47.4 ms
lava	3 vedha	≈ 0.14 s
	3 lava	≈ 0.43 s
	3	≈ 1.28 s
	5	≈ 6.4 s
laghu	15	≈ 96 s (1.6 min)
danda (nadika)	15 laghu	≈ 1.44 ks (24 min)
	2 danda	≈ 2.88 ks (48 min)
(sidereal day)	30	≈ 86.4 ks (24 h)
masa (month)	30	≈ 2,592 ks
ritu (season)	2 masa	≈ 5,184 ks
ayana	3 ritu	≈ 15,552 ks (6 mth)
samvatsara (year)	2 ayana	≈ 31,104 ks
of Deva

Lunar metrics

The traditional lunar calendar system measures time based on the Moon's phases and its relation to the Sun. Unlike solar calendars, it uses units such as tithi (lunar day), pakṣa (lunar fortnight), māsa (lunar month), ṛitu (season), ayanam (half-year), and varsha (lunar year) to structure the year. This system was integral to ancient cultures for tracking time, planning festivals, and guiding agricultural practices. The following section provides an overview of these key time units and their relationships:Template:Sfn

Unit	Definition	Equivalence
tithi (lunar day)	Time for 12° increase of longitudinal angle between Moon and Sun	≈ 1 day (varies 19–26 hours)
(lunar fortnight)	15 tithis	≈ 15 days
(lunar month)	2 : gaura (bright) or during waxing moon; (dark) during waning moon	≈ 30 days (29.5 days)
(season)	2	≈ 60 days
ayanam	3	≈ 180 days
varsha (lunar year)	2 ayanams	≈ 360 days (354.36707 days)

Tropical metrics

Tropical metrics are time units used to measure intervals based on the tropical year and related cycles. This system includes units such as ghaṭi (base unit), yāma (a period of 7.5 ghaṭis), and ahorātram (a full day comprising 8 yāmas). The following section explains these units and their approximate durations, offering insight into how time is organized in relation to the tropical year:Template:SfnTemplate:Efn

Unit	Definition	Equivalence
()	base unit	≈ 24 minutes
()	7.5	≈ 3 hours
()	8	≈ 24 hours (tropical day starting at sunrise)

Cosmic metrics

The table below contains calculations of cosmic Hindu units of time as experienced by different entities, namely humans, Pitris (forefathers), Devas (gods), Manu (progenitor of humanity), and Brahma (creator god). Calculations use a traditional 360-day year (twelve 30-day months) and a standard 24-hour day for all entities.

Cosmic units of time

UnitTemplate:Efn	Definition	Human	Pitri	Deva	Manu	Brahma
	36,000 kalpa & pralaya	311,040,000,000,000 yr	10,368,000,000,000 yr	864,000,000,000 yr	~101,408,450.70 yr	100 yr
	length
	1⁄2	155,520,000,000,000 yr	5,184,000,000,000 yr	432,000,000,000 yr	~50,704,225.35 yr	50 yr
kalpa	14 m + 15 ms; 1,000 cy	4,320,000,000 yr	144,000,000 yr	12,000,000 yr	~1,408.45 yr	12 h
pralaya	kalpa length
manvantara [m]	71	306,720,000 yr	10,224,000 yr	852,000 yr	100 yr	51.12 min
[ms]	length	1,728,000 yr	57,600 yr	4,800 yr	~6.76 mo	17.28 s
[cy]	, , & Kali-yugas	4,320,000 yr	144,000 yr	12,000 yr	~1.41 yr	43.20 s
	sum total	1,728,000 yr	57,600 yr	4,800 yr	~6.76 mo	17.28 s
	1⁄10 Template:Efn length	144,000 yr	4,800 yr	400 yr	~16.90 day	1.44 s
Template:Efn	4 Kali-yugaTemplate:Efn lengths	1,440,000 yr	48,000 yr	4,000 yr	~5.63 mo	14.40 s
	sum total	1,296,000 yr	43,200 yr	3,600 yr	~5.07 mo	12.96 s
	1⁄10 Template:Efn length	108,000 yr	3,600 yr	300 yr	~12.68 day	1.08 s
Template:Efn	3 Kali-yugaTemplate:Efn lengths	1,080,000 yr	36,000 yr	3,000 yr	~4.23 mo	10.80 s
	sum total	864,000 yr	28,800 yr	2,400 yr	~3.38 mo	8.64 s
	1⁄10 Template:Efn length	72,000 yr	2,400 yr	200 yr	~8.45 day	0.72 s
Template:Efn	2 Kali-yugaTemplate:Efn lengths	720,000 yr	24,000 yr	2,000 yr	~2.82 mo	7.20 s
Kali-yuga	sum total	432,000 yr	14,400 yr	1,200 yr	~1.69 mo	4.32 s
	1⁄10 Kali-yugaTemplate:Efn length	36,000 yr	1,200 yr	100 yr	~4.23 day	0.36 s
Kali-yugaTemplate:Efn	1,000 Deva years	360,000 yr	12,000 yr	1,000 yr	~1.41 mo	3.60 s

Lifespans

Hindu texts define lifespans differently for humans, Pitris (forefathers), Devas (gods), Manus (progenitors of mankind), and Brahma (creator god). The division of a year for each is twelve 30-day months or 360 days, where a day is divided into a 12-hour day proper and 12-hour night. A 30-day month amounts to four 7-day weeks with an extra 8th day every two weeks (48-week year). A traditional human year is measured by the sun's northern (uttarayana) and southern (dakshinayana) movements in the sky,Template:Efn where the new year commences only when the sun returns to the same starting point and a pause on the commencement otherwise. Ebenezer Burgess postulates an intercalary month was inserted every five years to anciently maintain the correspondence of the 360-day years with the true solar years (~365.24-day years).Template:Sfn For this reason, a traditional 360-day year is equivalent to a modern ~365.24-day solar or tropical year.

UnitTemplate:Efn	Human	Pitri	Deva	Manu	Brahma
Brahma year	3,110,400,000,000 yr	103,680,000,000 yr	8,640,000,000 yr	~1,014,084.51 yr	1 yr
Manu year	3,067,200 yr	102,240 yr	8,520 yr	1 yr	30.67 s
Deva year	360 yr	12 yr	1 yr	~1.01 h	3.60 ms
Pitri year	30 yr	1 yr	1 mo	~5.07 min	300 μs
Human year	1 yr	12 day	1 day	~10.14 s	10 μs

Cosmic date

According to Puranic sources,Template:Efn Krishna's departure marks the end of the human age of Dvapara-yuga and the start of Kali-yuga, which is dated to midnight on 17/18 February 3102BCE of the proleptic Julian calendar. We are currently halfway through Brahma's life (maha-kalpa), whose lifespan is equal to the duration of the manifested material elements, from which Brahma manifests his universe in kalpa cycles:Template:SfnTemplate:Sfn

• 51st year of 100 (2nd half or parardha)
• 1st month of 12
• 1st kalpa (Shveta-Varaha Kalpa) of 30
• 7th manvantara (Vaivasvatha Manu) of 14
• 28th chatur-yuga of 71
• 4th yuga (Kali-yuga) of 4

A maha-kalpa is followed by a maha-pralaya (full dissolution) of equal length. Each kalpa (day of Brahma) is followed by a pralaya (night of Brahma or partial dissolution) of equal length. Preceding the first and following each manvantara is a manvantara-sandhya (connection period), each with a length of Krita-yuga (Template:Aka Satya-yuga).Template:Sfn

Hindu texts specify that the start and end of each of the yugas are marked by astronomical alignments. This cycle's Treta-yuga began with 5 planets residing in the "Aries" constellation. This cycle's Dvapara-yuga ended with the "Saptarshi" constellation (Ursa major) residing in the "Magha" constellation. The current Kali-yuga will end with the Sun, Moon and Jupiter residing in the "Pushya" sector.Template:Better source needed

Human

The history of humanity is divided up into four yugas (Template:Aka dharmic ages or world ages)— (pronounced Krita-yuga; Template:Aka Satya-yuga), , and Kali-yuga—each with a 25% decline in dharmic practices and length, giving proportions (; pronounced charanas) of 4:3:2:1 (e.g. Satya: 100% start; Kali: 25% start, 0% end), indicating a de-evolution in spiritual consciousness and an evolution in material consciousness. Kali-yuga is followed by Satya-yuga of the next cycle, where a cycle is called a (pronounced chatur-yuga; Template:Aka mahā-yuga). Each yuga is divided into a main period (Template:Aka yuga proper) and two yuga-sandhis (Template:Aka ; connecting periods)⁠— (dawn) and (Template:Aka ; dusk)⁠—where each yuga-sandhi lasts for 10% of the main period. Lengths are given in divine years (Template:Aka celestial or Deva years), where a divine year lasts for 360 solar (human) years. A chatur-yuga lasts for 4.32 million solar (12,000 divine) years with 1,728,000 years of Krita-yuga, 1,296,000 years of Treta-yuga, 864,000 years of Dvapara-yuga, and 432,000 years of Kali-yuga.Template:SfnTemplate:Efn

Current yuga

Kali-yuga lasts for 432,000 years and is the 4th of 4 yugas in a cycle as well as the current yuga, with two sandhyas, each lasting for 36,000 years:Template:Efn

• Kali-yuga started 3102BCE in past:

= current year + Kali-yuga start year - year zero

= 2026 + 3102 - 1

= years

• Kali-yuga-sandhya (dawn) ends CE in future:

= Kali-yuga-sandhya - elapsed Kali-yuga

= 36,000 - (2026 + 3102 - 1)

= years

• Kali-yuga-sandhyamsa (dusk) starts CE in future:

= Kali-yuga - Kali-yuga-sandhyamsa - elapsed Kali-yuga

= 432,000 - 36,000 - (2026 + 3102 - 1)

= years

• Kali-yuga ends CE in future:

= Kali-yuga - elapsed Kali-yuga

= 432,000 - (2026 + 3102 - 1)

= years

Current chatur yuga

A chatur-yuga lasts for 4.32million years, where the current is the 28th of 71:Template:Efn

• Started BCE in past:

= chatur-yuga - Kali-yuga + elapsed Kali-yuga

= 4,320,000 - 432,000 + (2026 + 3102 - 1)

= years

≈ million years

• Ends CE in future:

= Kali-yuga - elapsed Kali-yuga

= 432,000 - (2026 + 3102 - 1)

= years

28th chatur-yuga

Yuga	Start (– End)	Length
Krita (Satya)	3,891,102BCE	1,728,000 (4,800)
Treta	2,163,102BCE	1,296,000 (3,600)
Dvapara	867,102BCE	864,000 (2,400)
Kali*	3102BCETemplate:Snd428,899CE	432,000 (1,200)
Years: 4,320,000 solar (12,000 divine)
(*) Current.		Template:EfnTemplate:SfnTemplate:Sfn

Pitri

The lifespan of the Pitris (forefathers) lasts for 100 of their years.Template:Sfn

• 24 hours (1 day & night) of Pitris = 1 solar month (masa; Moon's two 15-day fortnights: bright and dark)
• 30 days (1 month) of Pitris = 30 solar months (2.5 solar years)
• 12 months (1 year) of Pitris = 30 solar years (1 month of Devas)
• 100 years (lifespan) of Pitris = 3,000 solar years

Deva

The lifespan of the Devas (gods) lasts for 100 of their years.Template:Sfn

• 24 hours (1 day & night) of Devas = 1 solar year (Sun's two 180-day motions: northern and southern)
• 30 days (1 month) of Devas = 30 solar years (1 year of Pitris)
• 12 months (1 year) of Devas = 360 solar years
• 100 years (lifespan) of Devas = 36,000 solar years

Manu

The lifespan of the Manus (progenitors of mankind) lasts for 100 of their years. Each Manu reigns over a period called a manvantara, each lasting for 71 chatur-yugas (306.72 million years). A total of 14 Manus reign successively in one kalpa (day of Brahma). Preceding the first and following each manvantara is a (connection period), each lasting the duration of Satya-yuga (1.728 million years). During each (Template:Aka manvantara-sandhi), Earth (Bhu-loka) is submerged in water.Template:Sfn

• 24 hours (1 day & night) of Manu = 8,520 solar years
• 30 days (1 month) of Manu = 255,600 solar years
• 12 months (1 year) of Manu = 3,067,200 solar years
• 100 years (lifespan) of Manu = 306,720,000 solar years (71 chatur-yugas)

Current manvantara

A manvantara lasts for 306.72million years, where the current (ruled by Vaivasvatha Manu) is the 7th of 14:Template:Efn

• Started in past:

= elapsed 28th chatur-yuga + 27 chatur-yugas

= chatur-yuga - Kali-yuga + elapsed Kali-yuga + 27 chatur-yugas

= (4,320,000 - 432,000 + (2026 + 3102 - 1)) + 4,320,000 * 27

= years

≈ million years

• Ends in future:

= remaining 28th chatur-yuga + 43 chatur-yugas

= Kali-yuga - elapsed Kali-yuga + 43 chatur-yugas

= (432,000 - (2026 + 3102 - 1)) + 4,320,000 * 43

= years

≈ million years

Brahma

The lifespan of Brahma (creator god) lasts for 100 of his years. His 12-hour day or kalpa (Template:Aka day of Brahma) is followed by a 12-hour night or pralaya (Template:Aka night of Brahma) of equal length, each lasting for 4.32 billion years. A kalpa lasts for 1,000 chatur-yugas and has 14 manvantaras and 15 manvantara-sandhyas occurring in it. At the start of Brahma's days, he is re-born and creates the planets and the first living entities. At the end of his days, he and his creations are unmanifest (partial dissolution). His 100-year life (311.04 trillion years) is called a , which is followed by a (full dissolution) of equal length, where the bases of the universe, prakriti, is manifest at the start and unmanifest at the end of a maha-kalpa. His 100-year life is divided into two 50-year periods, each called a .Template:Sfn In 100 360-day years (maha-kalpa), there are a total of 36,000 full days: 36,000 kalpas (days proper) and 36,000 pralayas (nights).

• 12 hours (1 day proper: kalpa) of Brahma = 4.32 billion solar years (1,000 chatur-yugas; 14 manvantaras + 15 manvantara-sandhyas)
• 24 hours (1 day & night: kalpa + pralaya) of Brahma = 8.64 billion solar years
• 30 days (1 month) of Brahma = 259.2 billion solar years
• 12 months (1 year) of Brahma = 3.1104 trillion solar years
• 50 years (parardha) of Brahma = 155.52 trillion solar years
• 100 years (lifespan: 2 parardhas) of Brahma = 311.04 trillion solar years

Current kalpa

A kalpa (day of Brahma, 12 hours) lasts for 4.32billion years, where the current (Shveta-Varaha Kalpa) is the 1st of 30 in his 1st month of his 51st year:Template:Efn

• Started in past:

= elapsed 7th manvantara + 7 manvantara-sandhyas + 6 manvantaras

= elapsed 28th chatur-yuga + 27 chatur-yugas + 7 manvantara-sandhyas + 6 manvantaras

= chatur-yuga - Kali-yuga + elapsed Kali-yuga + 27 chatur-yugas + 7 manvantara-sandhyas + 6 manvantaras

= ((4,320,000 - 432,000 + (2026 + 3102 - 1)) + 4,320,000 * 27) + 1,728,000 * 7 + 306,720,000 * 6

= years

≈ billion years

• Ends in future:

= remaining 7th manvantara + 8 manvantara-sandhyas + 7 manvantaras

= remaining 28th chatur-yuga + 43 chatur-yugas + 8 manvantara-sandhyas + 7 manvantaras

= Kali-yuga - elapsed Kali-yuga + 43 chatur-yugas + 8 manvantara-sandhyas + 7 manvantaras

= ((432,000 - (2026 + 3102 - 1)) + 4,320,000 * 43) + 1,728,000 * 8 + 306,720,000 * 7

= years

≈ billion years

Current maha kalpa

A maha-kalpa (life of Brahma) lasts for 311.04trillion years:Template:Efn

• Started in past:

= elapsed 18,001st kalpa + 18,000 kalpas + 18,000 pralayas

= elapsed 7th manvantara + 7 manvantara-sandhyas + 6 manvantaras + 36,000 kalpas/pralayas

= elapsed 28th chatur-yuga + 27 chatur-yugas + 7 manvantara-sandhyas + 6 manvantaras + 36,000 kalpas/pralayas

= chatur-yuga - Kali-yuga + elapsed Kali-yuga + 27 chatur-yugas + 7 manvantara-sandhyas + 6 manvantaras + 36,000 kalpas/pralayas

= (((4,320,000 - 432,000 + (2026 + 3102 - 1)) + 4,320,000 * 27) + 1,728,000 * 7 + 306,720,000 * 6) + 4,320,000,000 * 36,000

= years

≈ trillion years

• Ends in future:

= remaining 18,001st kalpa + 17,999 kalpas + 18,000 pralayas

= remaining 7th manvantara + 8 manvantara-sandhyas + 7 manvantaras + 35,999 kalpas/pralayas

= remaining 28th chatur-yuga + 43 chatur-yugas + 8 manvantara-sandhyas + 7 manvantaras + 35,999 kalpas/pralayas

= Kali-yuga - elapsed Kali-yuga + 43 chatur-yugas + 8 manvantara-sandhyas + 7 manvantaras + 35,999 kalpas/pralayas

= (((432,000 - (2026 + 3102 - 1)) + 4,320,000 * 43) + 1,728,000 * 8 + 306,720,000 * 7) + 4,320,000,000 * 35,999

= years

≈ trillion years

Hindu texts

Mahabharata

The Mahabharata (12.231.12–31) describes units of time from a wink of the eye (nimesha) up to the days (kalpa) and nights (pralaya) of Brahma.

(12–13) The Rishis, measuring time, have given particular names to particular portions. Five and ten winks of the eye make what is called a Kashtha. Thirty Kashthas make what is called a Kala. Thirty Kalas, with the tenth part of a Kala, make a Muhurta. Thirty Muhurtas make up one day and night. Thirty days and nights form a month, and twelve months form a year.

(14) Persons well-read in mathematical science say that a year is made up of two solar motions, viz, the northern and the southern.

(15) The sun makes the day and the night for men. The night is for the sleep of all living creatures and the day is for work.

(16) A month of human beings is equal to a day and night of the departed manes. That division consists in this the light half of the month is their day which is for work, and the dark fortnight is their night for sleep.

(17) A year (of men) is equal to a day and night of the gods. This division consists in this the half year for which the sun travels from the vernal to the autumnal equinox is the day of the gods, and the half year for which the sun moves from the latter to the former is their night.

(18) Calculating by the days and nights of human beings about which I have told you I shall speak of the day and night of Brahman [(Brahma)] and his years also.

(19) I shall, in their order, tell you the number of years that are for different purposes calculated differently, in the Krita, the Treta, the Dwapara, and the Kali yugas.

(20) Four thousand celestial years is the duration of the first or Krita age. The morning of that cycle consists of four hundred years and its evening is of four hundred years.

(21) Regarding the other cycles, the duration of each gradually decreases by a quarter in respect of both the principal period with the minor portion and the conjoining portion itself.

(29) The learned say that these twelve thousand celestial years form what is called a cycle. A thousand such cycles form a single day of Brahman [(Brahma)].

(30) The same is the duration of Brahman's [(Brahma's)] night. With the beginning of Brahman's [(Brahma's)] day the universe begins to come into being. During the period of universal dissolution the Creator sleeps in Yoga meditation. When the period of sleep expires, He awakes.

(31) What is Brahman's [(Brahma's)] day covers a thousand such cycles. His night also covers a thousand similar cycles. They who know this are said to know the day and the night.

— Mahabharata, Book 12 (Shanti Parva), Ch. 231Template:Efn

Manusmriti

The Manusmriti (Template:Aka Laws of Manu; 1.64–80) describes units of time from a twinkling of the eye (nimesha) up to the days (kalpa) and nights (pralaya) of Brahma.

(64) Eighteen nimeshas (twinklings of the eye, are one kashtha), thirty kashthas one kala, thirty kalas one muhurta, and as many (muhurtas) one day and night.

(65) The sun divides days and nights, both human and divine, the night (being intended) for the repose of created beings and the day for exertion.

(66) A month is a day and night of the manes, but the division is according to fortnights. The dark (fortnight) is their day for active exertion, the bright (fortnight) their night for sleep.

(67) A year is a day and a night of the gods; their division is (as follows): the half year during which the sun progresses to the north will be the day, that during which it goes southwards the night.

(68) But hear now the brief (description of) the duration of a night and a day of Brahman [(Brahma)] and of the several ages (of the world, yuga) according to their order.

(69) They declare that the Krita age (consists of) four thousand years (of the gods); the twilight preceding it consists of as many hundreds, and the twilight following it of the same number.

(70) In the other three ages with their twilights preceding and following, the thousands and hundreds are diminished by one (in each).

(71) These twelve thousand (years) which thus have been just mentioned as the total of four (human) ages, are called one age of the gods.

(72) But know that the sum of one thousand ages of the gods (makes) one day of Brahman [(Brahma)], and that his night has the same length.

(73) Those (only, who) know that the holy day of Brahman [(Brahma)], indeed, ends after (the completion of) one thousand ages (of the gods) and that his night lasts as long, (are really) men acquainted with (the length of) days and nights.

(79) The before-mentioned age of the gods, (or) twelve thousand (of their years), being multiplied by seventy-one, (constitutes what) is here named the period of a Manu (Manvantara).

(80) The Manvantaras, the creations and destructions (of the world, are) numberless; sporting, as it were, Brahman [(Brahma)] repeats this again and again.

— Manusmriti, Ch. 1

According to Patrick Olivelle, most scholars take the table of contents (1.111–118) to be an addition, but for him the account of time and cosmology (1.61–86) to the aforementioned (1.118) are out of place redactions. He feels the narrative should have ended when the initial command to "listen" (1.4) was repeated (1.60), then transition to "learn" (2.1).Template:Sfn

Georg Bühler, whose translation has remained the standard for over a century according to Olivelle, translated 1.71 as 12,000 years in a four-aged period, same as Sir William Jones's translation, both based on Kulluka Bhatta's commentary. Medhatithi translated it as 12,000 four-aged periods in an age of the gods. Kulluka and Olivelle reject Medhatithi's interpretation based on 1.79 mentioning 12,000 without a qualifier ("etat" or "this") and must be assumed as years.

Surya Siddhanta

The Surya Siddhanta (1.10–21) describes units of time from a respiration (prana)Template:Sfn up to the 100-year lifespan of Brahma (maha-kalpa).

(10) Time is the destroyer of the worlds; another Time has for its nature to bring to pass. This latter, according as it is gross or minute, is called by two names, real (murta) and unreal (amurta).

(11) That which begins with respirations (prana) is called real; that which begins with atoms (truti) is called unreal. Six respirations make a vinadi, sixty of these a nadi;

(12) And sixty nadis make a sidereal day and night. Of thirty of these sidereal days is composed a month; a civil (savana) month consists of as many sunrises;

(13) A lunar month, of as many lunar days (tithi); a solar (saura) month is determined by the entrance of the sun into a sign of the zodiac : twelve months make a year. This is called a day of the gods.

(14) The day and night of the gods and of the demons are mutually opposed to one another. Six times sixty [360] of them are a year of the gods, and likewise of the demons.

(15) Twelve thousand of these divine years are denominated a Quadruple Age (caturyuga); of ten thousand times four hundred and thirty-two [4,320,000] solar years

(16) Is composed that Quadruple Age, with its dawn and twilight. The difference of the Golden and the other Ages, as measured by the difference in the number of the feet of Virtue in each, is as follows:

(17) The tenth part of an Age, multiplied successively by four, three, two, and one, gives the length of the Golden and the other Ages, in order : the sixth part of each belongs to its dawn and twilight.

(18) One and seventy [71] Ages are styled here a Patriarchate (manvantara); at its end is said to be a twilight which has the number of years of a Golden Age, and which is a deluge.

(19) In an Æon (kalpa) are reckoned fourteen such Patriarchs (manu) with their respective twilights; at the commencement of the Æon is a fifteenth dawn, having the length of a Golden Age.

(20) The Æon, thus composed of a thousand Ages, and which brings about the destruction of all that exists, is styled a day of Brahma; his night is of the same length.

(21) His extreme age is a hundred, according to this valuation of a day and a night...

— Surya Siddhanta, Ch. 1

External links

• Scientific Explanation of Hindu Time Units
• Surya Siddhanta, Chapter I with Commentary and Illustrations