Content rating
Everyone
5+
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Content rating
Everyone
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About this app

Transform yourself in 42 days.

42 is the fitness challenge app that builds life-changing habits. Commit to 42 days of consistent workouts, track every session, and watch your fitness score climb from Beginner to Elite.

WHY 42 DAYS?
Research shows it takes 42 days — 6 weeks — to truly build a habit that sticks. Enough time to make exercise feel automatic, not forced.

YOUR FITNESS SCORE
42 calculates a real-time fitness score (0–100) based on three factors:
• Consistency — how often you show up
• Effort — how hard you push
• Volume — how long you train

Level up from Beginner → Building → Active → Athlete → Elite as you progress through the challenge.

KEY FEATURES
• Log any workout — Run, Ride, Walk, Swim, Gym, Yoga, and more
• GPS distance tracking for outdoor runs and rides
• Circular gauge dials showing days left and fitness score
• Weekly summary with active days, total minutes, and score change
• 11 achievement badges to unlock as you hit milestones
• Calendar view — see every workout and rest day at a glance
• Progress chart tracking your fitness score across all 42 days
• Daily reminder notifications to keep your streak alive
• Add workout photos or selfies to remember your best sessions
• Share your progress card with friends and family
• Rest day logging — intentional recovery counts too
• Swipe to edit or delete any workout

ACHIEVEMENT BADGES
Unlock 11 badges as you progress:
First Sweat · Hat Trick · Week One · Dedicated · Week Two · On Fire · Halfway There · Warrior · Week Four · Home Stretch · 42-Day Champion

HOW IT WORKS

1. Tap "Begin Today" to start your 42-day challenge
2. Log each workout — pick the type, duration, and how you felt
3. Watch your fitness score and progress ring update in real time
4. Hit milestones and unlock achievement badges along the way
5. Share your final result on Day 42

YOUR DATA STAYS WITH YOU
All workout data is stored privately on your device. No account required. No subscription. No cloud sync.

Start your 42-day transformation today.
Updated on
Jun 19, 2026

Data safety

Safety starts with understanding how developers collect and share your data. Data privacy and security practices may vary based on your use, region, and age. The developer provided this information and may update it over time.
No data shared with third parties
Learn more about how developers declare sharing
No data collected
Learn more about how developers declare collection

What’s new

Apple Health Integration

Workouts from Apple Watch and other health apps automatically sync into your 42-day challenge
Daily step count displayed on the Home screen
Manual sync button to pull in workouts on demand
Heart rate and calories imported from Health
Improvements

Progress Breakdown score display fixed (no more wrapping on "100")
Version bumped across iOS and Android
Content rating
Everyone
Learn more

App support

About the developer
TE WEN CHIU
tewen.chiu@gmail.com
United States