量度是对一物理量（如长度、尺寸或容量等）的估计或测定，通常以一标准或度量衡。量度以数字单位的标准来表示，如距离即以多少哩或多少公里来表示。量度是大部份自然科学、技术、经济学及其他社会科学中定量研究的基础。

量度的过程为估计一数量的多寡和相同类型（如长度、时间、重量等）一单位的多寡之间的比例。量度即为此过程的结果，表示为数字加上一个单位，其中实数为估计的比例。如9公尺，其便为物体长度和长度单位，即公尺之间的比例。不像计数和整数个数个物体一般地可精确知道，每一个量度都是个存在些许不确定性的估计。量度包括了测量尺度（包括量值）、计量单位及不确定性。透过量度可以比较不同的量测，并且减少误会。有关量度的科学称为度量衡学。

Measurement is the assignment of a number to a characteristic of an object or event, which can be compared with other objects or events. The scope and application of a measurement is dependent on the context and discipline. In the natural sciences and engineering, measurements do not apply to nominal properties of objects or events, which is consistent with the guidelines of the International vocabulary of metrology published by the International Bureau of Weights and Measures. However, in other fields such as statistics as well as the social and behavioral sciences, measurements can have multiple levels, which would include nominal, ordinal, interval, and ratio scales.