The best free and fun workout app to build muscle or lose weight fast.
Turn the gym into a game with Flex. Compete with friends, compare your progress with world rankings, and connect with others in the community.
Yes, really free with no ads and no catches. Premium offers a better experience with features like auto progression and logging on Apple Watch.
Follow us and our craziness:
- Instagram @flex.ai
- Tiktok @flex.app
- flexfitnessapp.com

Free:
• Basic premade workout programs
• Build or customize your own program and freestyle workouts
• Workout guide and logger
• Share your workouts and routines with friends
• View your progress and stay consistent: workout calendar, exercise stats, streak, bodyweight tracker, calories tracker, steps tracker, workout notifications

Flex Premium:
• Logging on the Apple Watch app
• Auto Progression: Automatically increases or decreases the difficulty of your logged exercises next session.
• Unlock Premium programs
• Unlock Premium freestyle workouts
• Premium workout experience: music integration, plate calculator, etc.

Flex is the free, simple, and engaging app that does the planning and tracking so that you can just focus on your workouts and achieve your goals. Flex can automatically increase or decrease the difficulty of your exercises in your program based on past performance.

Hundreds of workouts and programs for you. Find and use the most effective workouts and programs designed by personal trainers, tailored to your goal and whether you workout at the gym or at home.

Forget about researching exercises, programs and keeping track of all your progress. Flex handles that and makes working out more engaging with features like streaks and progress charts.

Freestyle workouts:
Whatever your time commitment, physical goals, experience, or access to equipment, Flex has the right workouts for you. Choose any combination of equipment, goals, muscles worked or quick freestyle workouts.

Already have a fitness program you use or want to customize your own?
Edit one of our programs or build your own into Flex with the custom plan builder.

Real-Time Workout Guide:
Flex’s workout guide will lead you through your workout step by step, telling you which exercises to do, how to do them, how long to rest for optimal results and notifying you when you need to start your next set. You also have the spreadsheet view where you can fully modify your workout on the fly. Move around exercises, change exercises, add/remove sets. Control your music without leaving the app thanks to native Spotify and Apple Music integrations.

You can't improve what you don't measure. With Flex, you can track:

How consistently you’re exercising with the calendar feature
Your total calories burned daily, calculated from workouts/steps/BMR
Your bodyweight over time
Your steps with a 10k daily goal via the Apple Health integration
Your exercise progress with the exercise stats
Your workout history

An even easier way to workout with Flex Apple Watch:
Use the Flex apple watch app to log sets and complete workouts without needing to constantly check your phone. Sync your data and close your activity rings.