A Yojana (Sanskrit : योजन ) is a Vedic measure of distance that was used in ancient India. It is equivalent to about 8 miles as per modern measures of distance, though the exact value is disputed among scholars (between 5 to 8 miles).
In modern Hindi the word yojanaa (Hindi : योजना) means "plan" or blueprint, and is etymologically connected with the Cartesian notion of distance in the word yojana. However, note that the words "yojana'" and "yojanaa" are different, and pronounced differently. The last sound of the second word is pronounced "aa" as in arm [ārm].
Variations on length
The length of the yojana varies depending on the different standards adopted by different Indian astronomers. In the Surya Siddhanta of the 5th century, for example, a yojana was equivalent to 5 miles, and the same was true for Aryabhata's Aryabhatiya (499). However, by the time of Paramesvara in the 14th century, the yojana was defined to be about 1.5 times larger than it was in Aryabhata's time, thus being equivalent to about 8 miles.
Religious leader A. C. Bhaktivedanta Swami Prabhupada gives the equivalent length of a yojana as 8 miles (12,8 km)  throughout his translations of the Bhagavata Purana. Some traditional Indian scholars give measurements between 13 km and 16 km (8–10 miles) or thereabouts. Alexander Cunningham, in The Ancient Geography of India, takes a yojana to mean 8 miles.
Height of meru parvat is estimated to be 1,00,000 yojan in jain cosmology where 1 yojan is given as 4000 miles. If the length of a Yojana is taken to be approximately 8 to 10 miles (13–16 km), like it was in later times, then its subsidiary measurements are as follows:
- 1 angula = 16 mm to 21 mm
- 4 angulas = one dhanu graha (bow grip) = 62 mm to 83 mm;
- 8 angulas = one dhanu musti (fist with thumb raised) = 125 mm to 167 mm;
- 12 angulas = 1 vitasti (handspan: distance between tip of thumb and tip of last finger when palm is stretched) = 188 mm to 250 mm
- 2 vitastis = 1 aratni (cubit) = 375 mm to 500 mm
- 4 aratnis = 1 danda = 1.5 to 2.0 m
- 2 dandas = 1 dhanu = 3 to 4 m
- 5 dhanus = 1 rajju = 15 m to 20 m
- 2 rajjus = 1 paridesha = 30 m to 40 m
- 100 parideshas = 1 krosha (or gorata) = 3 km to 4 km
- 4 kroshas = 1 yojana = 13 km to 16 km
- 1,000 yojanas = 1 Mahayojan = 13 Mm to 16 Mm
- Richard Thompson (1997), "Planetary Diameters in the Surya-Siddhanta", Journal of Scientific Exploration 11 (2): 193–200 
- O'Connor, John J.; Robertson, Edmund F., "Aryabhata I", MacTutor History of Mathematics archive, University of St Andrews.
- Srimad Bhagavatam 10.57.18 (translation) "one yojana measures about eight miles"