Land use and marine spatial planning processes are increasingly supported by systematic assessment techniques, particularly by multi-criteria spatial analysis methods. This has been facilitated by the growing release and uptake of web-mapping tools, which contribute to transparent, consistent, and informed planning processes and decisions. This article reviews the usability, functionality, and applicability of contemporary planning web-mapping tools to identify the state-of-the-art and future prospects. The review reveals that interfaces are increasingly available and intuitively applicable by non-specialized users. Basic map navigation and data querying functionality is being expanded to incorporate advanced map-making and online data geoprocessing capabilities that enable deriving new data and insights. However, the majority of published planning web tools are one-off solutions, and a disconnect between research and practice is rendering many of these inaccessible or obsolete. Despite the significant progress made in advancing their provision in the last decade, there is a need for developing transferable interfaces that are maintained beyond project end dates, for them to effectively and consistently support planning processes.