The catty, kitty 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 spelt tahil), 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. The word catty originated from the Malay word kati and that spelling is used in Malay and English today when referring to the weight in Brunei, Indonesia, Malaysia, and Singapore where it is still used in some contexts especially related to the significant Overseas Chinese population.
The catty is traditionally equivalent to around 1⅓ pound avoirdupois, formalised as 604.78982 grammes in Hong Kong, 604.79 grammes in Malaysia and 604.8 grammes in Singapore. In some countries, the weight has been rounded to 600 grammes (Taiwan and Thailand). In mainland China, the catty has been rounded to 500 grammes and is referred to as the market catty or kitty (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.