One of the most challenging questions surrounding subjective animal welfare is whether these states are measurable: that is, is subjective welfare an appropriately quantifiable target for scientific enquiry and ethical and deliberative calculation? The availability of several different types of measurement scale raises important questions regarding whether subjective experience has the right properties to be meaningfully represented on the types of scale required for different applications. This methodological question has so far received scant attention in the animal welfare literature. In (...) this paper, I address this omission by examining the types of measurement scale we can reasonably expect to apply to animal welfare measurements, and which we will actually need for our applications. I argue that our different applications will require variously ordinal, interval, and ratio scales, and that we have sufficient reason to believe that subjective welfare is a target with the appropriate characteristics to justify the practice of representing it using each of these types of scales. (shrink)