In Indian Vedas, the time calculated ( thousands of year ago) was more accurate than our current seconds, Minutes & Hours system.

Most of the Purana and the Vedas mentions about the time very clearly and accurately. Most of the astrological calculations and predictions was made on this time concepts.

Below, please see the "Kaalaparimana"- the time calculations

"If a strong man strike with a sharp needle on two lotus pedals kept one above the other, the time taken by the nozzle of the needle to pass one pedal to the other is called "ALPAM".
( Sri Maha Bhagavat, Ayush's kaalaparimaanam )

30 Alpam = 1 Thrudi

30 Thrudi = 1 Kala

30 Kala = 1 Kaashta or Nimisham or Maathra ( One second )

4 Maathra = 1 Ganitham

10 Ganitham = 1 Veerpu

6 Veerpu = 1 Vinazhika

60 Vinazhika = 1 Naazhika or Ghadika

60 Naazhika = 1 Maanam or Din or Divasa or Aahoratram ( One Day )

15 Maanam = 1 Paksham

2 Pakham = 1 Maasam or Maheena ( 1 Month )
( which is also known as one day of "Pithru Ganas" )

6 Maasam = 1 Ayanam

2 Ayanam = 1 Manusha Vaasaram or varsham or sal ( One Human Year )
( which is also known as one day of "Devas ( Angles )" )

1 Manusha Valsaram = 1 Deva divas ( one Angles day )

300 Deva's day = 1 Deva's Year ( Divya varham )
( 300 Human Year )

12000 Divya Valsaram = 1 Chathur Yug
( 3,600,000 Human Year )

Chathur Yug

Kritha Yug = 4800 Divya valsarom ( 1,440,000 Year )
Thretha Yug = 3600 Divya valsarom ( 1,080,000 Year )
Dwaapar Yug = 2400 Divya valsarom ( 720,000 Year )
Kali Yug = 1200 Divya valsarom ( 360,000 Year )

71 Chathur Yug = 1 Manuanthara
( the time of one Devendra, Manu, Saptharshis, Asura Raja...)
( 255,600,000 Human Year )

14 Manuanthara = 1 Deva Chathur Yug
( 3,578,400,000 Human Year )

1000 Deva Chathur Yug = 1 Brahma's Day time ( Half day )
( when the day of Brahma finishes everything created by him will
dissolve - Sri. Maha Bhaagavat )

2000 Deva chathur yug = 1 Brahma's full day
( 1000 Deva chathur yug ( 3,578,400,000,000 Human Year )
nothing will happen in this world and creates again after that )

360 Brahma's day = 1 Brhama Valsaram ( Brahma's year )

120 Brahma Valsarom = 1 Brahmaayush ( Brahma's Life time )
( it is called kalpanth and everything including Brahma & Siva
will dissolve to the super power - Vishnu and Vishnu enter to
Yoga nidra and the Devi the magnetic field dissolves to him too
and that stage Parbrahma -... Bhagavan Naraya )

References : Sri Maha Bhaagavat, Sri. Devi Bhaagavat, Garuda Purana ... )