In this paper, we present the Digital Language Vitality Scale, a tool for measuring the degree of digital vitality of languages. Digital vitality can be defined as the extent to which a language is present, used and usable over the Internet through digital devices. The scale is inspired to ethnolinguistic vitality assessment (such as GIDS, Fishman 2001), updated by (Lewis and Simons 2010) as EGIDS, and the UNESCO "nine factors" (UNESCO 2003), and is based on previous work in this area such as (Kornai 2013) and (Gibson 2015). Seven levels of digital vitality are identified, from "pre-digital" to "digitally thriving", and a set of associated indicators. The indicators associated with the scale are proxies representing both digital representation (presence) of a language and digital use. They are clustered into three groups: a first group of indicators refers to digital usability of a language, for instance, the existence of Internet connection or the availability of standardised fonts for writing the language. A second group of indicators is related to the quality and amount of digital use of a language: if and how much a language is used for texting and emailing, on websites, blogs, if there are e-books, Wikipedias, if the language is used on social media. The last group of indicators correlates with the digital prestige of a language; they are a sign of a language that not only is used on digital media and devices, but it is so in a full-fledged way, enjoying the widest possible ranges of uses and applications (e.g. localised digital services, machine translation, edu-tainment products and services). The scale is currently being used in the context of the DLDP project (http://www.dldp.eu) as an assessing instrument for digital language planning, with particular reference to regional and minority languages.