Postal Code Radius Tool

This tool calculates and visualizes postal code radii by returning nearby postal codes within a user-defined distance. It assists logistics planners, marketers, and site selectors to quantify catchment areas without GIS software. By using a central postal code and a country, the system cross-references a postal-code database and applies geospatial logic to derive candidate zones. Example: central_postal_code 10001 with radius 50 km yields a list of ZIP codes within that radius and a count of matches.
Conceptually, distances are computed from centroids using a geodesic method. The tool can operate in a geodesic mode by default, with an optional driving-distance mode that uses a routing service to estimate road-based distance and time when an API key is provided. This yields a more practical service-area view for delivery planning.
Who benefits: retailers validating store footprints, logistics teams structuring coverage, and marketing analysts mapping proximity-based audiences. The unique value lies in combining postal-code granularity with radius computation and optional routing data, all without heavy GIS tooling. Core features include input validation, support for multiple units, country-aware postal-code matching, and optional export formats.
Outputs are designed for downstream analytics: a set of nearby postal codes, their distances, a total count, and optional geographic formats suitable for import, visualization, or further calculations.