兰氏度（兰金，Rankine）是一个热力学温度单位。由英国工程师及物理学家威廉·约翰·麦夸恩·兰金在1859年提出，因而得名。现在已经几乎废弃不用。

兰金温标，又称为冉肯温标。其符号为（如果再细分为罗氏温标和列氏温标则以表示）。有时亦会写作， 但情况与绝对温标一样，是一种不正确的写法。兰金温标和绝对温标的零度皆为绝对零度，但兰金温标的间距是采用华氏温标，而绝对温标的间距则采用摄氏温标。而-459.67就等于0。

现时，只有在美国的少部分工程领域是以兰金温标作量度单位。而科学界大多依照国际单位制即绝对温标作为热力学温度的量度单位。

Rankine (/ˈræŋkɪn/) is a thermodynamic temperature based on an absolute scale named after the Glasgow University engineer and physicist William John Macquorn Rankine, who proposed it in 1859. (The Kelvin scale was first proposed in 1848.)

The symbol for degrees Rankine is °R (or °Ra if necessary to distinguish it from the Rømer and Réaumur scales). By analogy with kelvin, some authors call the unit rankine, omitting the degree symbol. Zero on both the Kelvin and Rankine scales is absolute zero, but the Rankine degree is defined as equal to one degree Fahrenheit, rather than the one degree Celsius used by the Kelvin scale. A temperature of 459.67 °R is exactly equal to 0 °F.