计量单位统一代码（英文：Unified Code for Units of Measure，缩写：UCUM）是一个用于向人和机器明确无歧地表示计量单位的代码系统。

此代码集（code set）之中收录着ISO 1000、ISO 2955-1983、ANSI X3.50-1986、HL7以及ENV 12435标准之中所定义的全部计量单位，而同时还明确采取可证实的方式，解决了这些标准之中在命名方面所存在的种种矛盾和分歧。UCUM为机器之间的通讯（machine to machine communication，机器通讯）提供7位ASCII码的计量单位表达形式，并且还备有区分大小写（case-sensitive）与不区分大小写（case-insensitive）的表达形式之间的明确映射。

The Unified Code for Units of Measure (the UCUM) is a system of codes for unambiguously representing measurement units to both humans and machines.

The code set includes all units defined in ISO 1000, ISO 2955-1983, ANSI X3.50-1986, HL7 and ENV 12435, but explicitly and verifiably addresses the naming conflicts and ambiguities in those standards to resolve them. It provides for representations of units in 7 bit ASCII for machine to machine communication, with unambiguous mapping between case-sensitive and case-insensitive representations.