水准尺是一种标有刻度的木质或铝质尺子，与水准仪配合使用，用于确定不同的高程。一般长约3~4米，按其构造不同可分为折尺、塔尺、直尺等数种。尺面每隔1厘米涂有黑白或红白相间的分格，每分米有数字注记。为倒像望远镜观测方便起见，注字常倒写。

A level staff, also called levelling rod, is a graduated wooden or aluminium rod, used with a levelling instrument to determine the difference in height between points or heights of points above a datum surface. It cannot be used without a leveling instrument.