C2K — Couch to 5K & 10K

C2K is a free, open-source running trainer for Android that guides you from the couch to running 5K or 10K — with no ads and no tracking.

Features:
• Couch to 5K (C25K) — 9-week program, 3 runs per week
• Couch to 10K (C210K) — 14-week program
• Audible voice prompts — "Start running", "Walk for 90 seconds", countdown warnings
• Background workout timer — continues with screen off
• GPS tracking (optional) — records distance and pace; works without GPS too
• Progress tracking — remembers which weeks and days you've completed
• Works offline — no internet permission required
• No proprietary services required — compatible with GrapheneOS and privacy-focused devices

Permissions:
• FOREGROUND_SERVICE — keeps the workout timer running with screen off
• WAKE_LOCK — prevents the CPU sleeping mid-workout
• ACCESS_FINE_LOCATION — optional GPS for distance/pace tracking (you can skip this)
• POST_NOTIFICATIONS — workout notification with pause/stop controls

C2K is free software released under the GNU General Public License v3.