The catty or kati (/ˈkɛtɪ/ in Singaporean English), symbol 斤, is a traditional Chinese unit of mass used across East and Southeast Asia, notably for weighing food and other groceries in some wet markets, street markets, and shops. Related units include the picul, equal to 100 catties, and the tael (also spelled tahil, in Malay / Indonesian), which is 1⁄16 of a catty. A stone is a former unit used in Hong Kong equal to 120 catties and a gwan (鈞) is 30 catties. Catty or kati is still used in South East Asia as a unit of measurement in some contexts especially by the significant Overseas Chinese populations of Brunei, Indonesia, Malaysia, and Singapore.
The catty is traditionally equivalent to around 1⅓ pound avoirdupois, formalised as 604.78982 grams in Hong Kong, 604.79 grams in Malaysia and 604.8 grams in Singapore. In some countries, the weight has been rounded to 600 grams (Taiwan, Japan and Thailand). In mainland China, the catty has been rounded to 500 grams and is referred to as the market catty (市斤 shìjīn) in order to distinguish it from the "metric catty" (公斤 gōngjīn), or kilogram, and it is subdivided into 10 taels rather than the usual 16.