Compare software

Intervals.icu vs Polar Flow: catalog facts
Intervals.icu	Polar Flow
Free Free to use.	Free Free to use with Polar devices.
Web	Android, iOS, Web
Detailed fitness, fatigue and power curve analytics Separate zones and metrics per sport	Syncs data from Polar watches and heart-rate monitors Available on the web and on phones
Web only, requires an account Analytics depth can be a lot for casual users	Only useful with Polar hardware Web service was under maintenance when checked
Web application	Downloadable app, Web application
Closed source	Closed source
License not stated	License not stated
Account needed	Not stated if an account is needed
Needs internet	Not stated if it works offline
Official website Full listing and sources Checked September 23, 2026	Official website Full listing and sources Checked September 23, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.