coyan or koyan

A unit of mass in Southeast Asia. In Sarawak, 3,098 pounds.


In Thailand, since 1923 a unit of mass, the standard koyan = 1200 kilograms. a unit of capacity = 80 thangsat (see thang, def. 2) = 2,645.54715 lb.

Earlier values:

The Bangkok coyan, used for rice and salt, 16.6305 koku.



The coyan, which is in reality a measure of capacity, is often used to designate a multiple of the hap [a unit of mass]. It is generally equal to 20 hap, although it ranges from 18 to 22 hap. The coyan of paddy is reckoned at about 16.6 hap and considered equal to 2133¹⁄₃ lbs.

Blockhuys, 1924. Page 61.

The last sentence requires a hap of ~128 pounds avoirdupois. The legal weight of the hap was 133.75 pounds avoirdupois, making the coyan of 18 hap = 2407.5 lb av; of 20 hap = 2675 lb. av.; of 22 hap = 2942.5 lb. av.

premetric coyan 20 piculs approximately 1,213.36 kilograms
coyan for rice 22 piculs approximately 1,334.7 kilograms
coyan for salt 25 piculs about 1,516.7 kilograms


Rice is sold by the coyan of one hundred baskets: a basket is supposed to be sufficient for the food of a man during a month.

John Bowring.
The Kingdom and People of Siam. Vol. 1.
London: 1857.
Page 202.


In Burma, 19ᵗʰ century, a unit of capacity = 100 tengs = 100 imperial bushels, about 3.637 cubic meters.


In Malaysia, the koyan, a unit of capacity = 40 pikuls or about 800 gantangs. The spelling is that of the 1972 spelling reform.


In the Netherlands East Indies, 19ᵗʰ – early 20ᵗʰ centuries, a measure of capacity for rice, grain and salt, varying by locality (ostensibly, it represents a weight of 30 picols).

Batavia coyan 27 picols
Samarang coyan 28 picols
Soerabaya coyan 30 picols

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