







量入为出 is a Chinese idiom (chengyu) meaning “to live within one's means”. To regulate expenditure by income; to cut one's coat according to one's cloth. Literally, “Measure income to determine expenditure”.
During the Three Kingdoms period, Cao Cao sent his subordinate, Wei Kai, to Bashu (modern-day Sichuan) to establish contact with Liu Zhang, the Governor of Yizhou. Upon arriving in Guanzhong, Wei Kai observed that the local powers were too strong and would potentially harm the interests of the Cao family, so he advised strengthening control over the region.
Later, after Cao Rui ascended to the throne, he embarked on extensive construction projects, building magnificent palaces. This extravagance caused immense suffering among the people of Guanzhong. Wei Kai then submitted a memorial to Cao Rui, urging him to determine the limits of national expenditure based on the income of the imperial treasury.