A free program for Android, by Blue Blink One SL.

Measure Map is a handy, accurate area and distance-measuring app that’s perfect for architects, geography enthusiasts, or anyone who simply needs to measure areas and distances on a map. Many features in the Measure Map Pro app make it user-friendly and beneficial. You may see various map sources (with an in-app purchase), create polygons, measure distances, areas, and perimeter lines, export data in the Measure Map, KML, CSV, Image (PNG), and PDF formats, and save images to picture albums. The program can also download routes and surfaces from the Internet. It’s free, so there’s no harm in giving it a try. Plus, it’s very easy to use.