Smithsonian's Global Volcanism Program (GVP) provides permanent unique identifiers (Volcano Numbers, or VNums) for volcanoes documented in the Volcanoes of the World (VOTW) database maintained by GVP and accessible at volcano.si.edu.

The International Association for Volcanology and Chemistry of Earth's Interior (IAVCEI), The World Organization of Volcano Observatories (WOVO), and the Global Volcano Model (GVM) have sanctioned GVP to assign numbers and primary names to the world's volcanoes. The purpose of the numbers is to prevent ambiguity regarding the name and location of volcanoes that may have non-unique names, or that are known by multiple names. The original VNums were based on a system developed in the 1950's for the IAVCEI Catalog of Active Volcanoes of the World (CAVW). GVP policy had been to embed significant geographical, historical, and age information in the numbers. As a result GVP often changed VNums, most frequently to accommodate newly recognized volcanoes in a particular geographical region, which over time undermined the goal of preventing ambiguity.

After moving VOTW to a new database platform, we developed a new VNum system and deployed the updated system on 30 September 2013. During this process GVP staff took into account the needs of the International Civil Aviation Organization (ICAO) and other stakeholders to have numbers compatible with modern computing systems. Holocene, Pleistocene, and Tertiary volcanoes all fall under the new unified numbering system, allowing interoperability between VOTW and new databases under development globally (e.g. WOVOdat, LaMEVE). Letters and characters (hyphens and equals signs) have been eliminated. Secondary numbers have been added for subfeatures associated with each volcano. None of the new numbers start with 0 or 1 to avoid confusion with the legacy system. While a connection remains to the older system, the geographic link to CAVW regions and subregions is no longer mandatory. In 2024 the region/subregion system was completely replaced with a Region Group / Volcanic Province assignments.

We feel that this change is in the best long-term interest of the community.