C2K — Couch to 5K & 10K

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

Programs:
• Pre-C25K — 3-week gentle starter for absolute beginners
• Couch to 5K (C25K) — 9-week program, 3 runs per week
• Bridge to 10K (B210K) — 6-week bridge for C25K graduates
• Couch to 10K (C210K) — 14-week program, continues from C25K
• One Hour Runner — 13-week progression from 30 to 60 minutes continuous running
• 5K Improver — 8-week speed and stamina program for runners who can already complete 5K

Features:
• Audible voice prompts — "Start running", "Walk for 90 seconds", countdown warnings
• Customizable coaching — adjust voice speed/volume, countdown warning timing, and mid-interval cues
• Vibration cues as an alternative or addition to voice
• Background workout timer — continues with screen off
• GPS tracking (optional) — records distance and pace; works without GPS too
• Treadmill mode — indoor runs without GPS
• Workout history — session log with total distance, time, best pace, longest run, and calorie estimates
• Progress tracking — remembers which weeks and days you've completed, with the option to reset
• In-app running guide — FAQ covering pacing, gear, and terminology
• Available in 7 languages — English, German, Spanish, French, Galician, Portuguese (Brazil), Russian
• 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
• VIBRATE — optional vibration cues during workouts

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

• Added manual language selection with locale-aware workout notifications and voice announcements.
• Added a voice test and actionable text-to-speech diagnostics in Settings.
• Added contributor credit for the language-selection contribution.