C2K — Couch to 5K & 10K

C2K is an offline running trainer that guides you from the couch to running 5K, 10K, and beyond. Follow a clear plan, hear hands-free coaching, and keep your progress private — 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
• Couch to 10K (C210K) — 14-week program, continues from C25K
• Bridge to 10K (B210K) — 6-week bridge for C25K graduates
• 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
• Test voice playback before a workout, with Android text-to-speech diagnostics
• Vibration cues as an alternative or addition to voice
• Smartwatch and fitness band alerts — interval changes arrive as notifications, so a paired Wear OS watch or Gadgetbridge band buzzes too. No watch app needed.
• Tones mode — short chimes instead of a voice for interval changes and countdowns
• Adjustable vibration strength and language selection
• Background workout timer — continues with screen off
• GPS tracking (optional) — records distance and pace; works without GPS too
• Treadmill mode — indoor runs without GPS
• Skip the warm-up or cool-down — in Settings, or with one tap during a workout
• Workout history — weekly streak, session log, totals, best pace, longest run and calorie estimates
• Progress tracking — remembers which weeks and days you've completed, with the option to reset
• Step back when it's tough — stop the same workout early twice and C2K suggests repeating the week before
• In-app running guide — FAQ covering pacing, gear, and terminology
• Available in 8 languages — English, German, Spanish, French, Galician, Portuguese (Brazil), Russian, Turkish
• Works offline — no internet permission required
• No proprietary services required — compatible with GrapheneOS and privacy-focused devices

Permissions:
• FOREGROUND_SERVICE (health, location) — keeps the workout timer running with the screen off
• ACTIVITY_RECOGNITION — Android requires it for a fitness timer that runs in the background; C2K reads no sensor data, and workouts still start if you decline
• ACCESS_FINE_LOCATION / ACCESS_COARSE_LOCATION — optional GPS distance and pace, only asked for workouts that use GPS
• POST_NOTIFICATIONS — the workout notification with pause and stop, and smartwatch alerts
• REQUEST_IGNORE_BATTERY_OPTIMIZATIONS — offers to exempt C2K from battery saving so it can't end a workout mid-run
• WAKE_LOCK — prevents the CPU sleeping mid-workout
• VIBRATE — optional vibration cues during workouts

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