Compare software

OpenCPN vs qtVlm: catalog facts
OpenCPN	qtVlm
Screenshots	Screenshots
Best for: Sailors who want a full chartplotter on a laptop or onboard computer	Best for: Cruising and racing sailors who plan routes around weather
Free Free and open source.	Free + paid options The GRIB viewer is free; mobile and tablet apps, chart packs and the GRIB service are paid.
Windows, macOS, Linux, Android	Windows, Android, iOS
Runs on Windows, macOS, Linux, Raspberry Pi and Android Plugin manager with a catalog of community plugins Designed for use at the helm while underway No cost for the software itself	Weather routing with departure-time comparison Reads S57, S63, raster and MBTiles charts AIS and NMEA instrument support Iridium GO certified
Desktop-style interface is less suited to phones than dedicated mobile apps Some chart sets must be obtained separately	Mobile versions and chart packs are paid Wide feature set takes time to learn
Downloadable app	Downloadable app
Open source	Not open source
License not stated	License not stated
No account needed	Not stated if an account is needed
Offline features available	Not stated if it works offline
Official website Full listing and sources Sources for OpenCPN opencpn.org play.google.com/store/apps/details Catalog checked September 23, 2026	Official website Full listing and sources Sources for qtVlm meltemus.com apps.apple.com/us/app/qtvlm/id999110023 Catalog checked September 24, 2026

“Not stated” means we have not confirmed it. Features can vary by device and plan.

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