Couch to 5K is a nine-week running program designed for complete beginners. This tracker guides you through every interval — telling you exactly when to run and when to walk, timing each segment, and saving your progress automatically.
Couch to 5K (C25K) is a nine-week running program that takes complete beginners from barely running a minute to running 30 continuous minutes — roughly a 5K for most people. You run three sessions per week, and each session follows a structured sequence of walking and running intervals that grow progressively longer.
Week 1 is mostly walking, with just 60-second running bursts separated by 90 seconds of walking. By week 9, you run for 30 uninterrupted minutes. The progression is slow by design. One of the most popular beginner running programs in the world, C25K was originally developed by Josh Clark in 1996 and has since helped millions of people become runners.
The key insight behind the program is that alternating walking and running lets your cardiovascular system and connective tissue adapt at a pace that prevents injury. You never jump from zero to sustained running — the body is given weeks to catch up to the demands being placed on it. That's why most people who follow the program through completion actually finish it without major setbacks, which is rare in beginner fitness programs.
Open the app and you'll see your current week and day. When you're ready to go, tap Start Session. The large timer display shows exactly how many seconds remain in the current segment, and the label above it tells you whether to run or walk.
Audio cues play automatically at every transition — a higher tone signals the start of a run interval, a lower tone signals the start of a walk interval, and countdown beeps warn you that a transition is three seconds away. You don't need to watch the screen the whole time.
When the session ends, your progress saves automatically to your browser and the app moves you to the next session. If you want to redo a session, tap the "Redo This Session" button before starting. All data lives locally in your browser — nothing is sent to a server, and nothing is lost between visits as long as you don't clear your browser storage.