Rust Strength
Know what weight to lift next
Only for iPhone
Free · Designed for iPhone. Not verified for macOS.
iPhone
Log a set with reps and how hard it felt. Rust Strength estimates your one-rep max and tells you what to load next, rounded to what the machine can actually be set to.
Rust Strength answers the question every lifter has mid-workout: how much should I put on the bar for the next set?
Log a set with the weight, the reps, and how hard it felt on the RPE scale. Rust Strength works out an estimated one-rep max from that, then suggests a weight for your next set aimed at reaching failure inside the rep range you chose. Every suggestion is rounded to a weight the machine in front of you can actually be set to, because a recommendation of 147 lb is useless on a stack that moves in tens.
BUILT FOR TRAINING IN DIFFERENT GYMS
Machines are not consistent. A chest press at one gym does not feel like a chest press at another, and plate-loaded, selectorised and cable setups all label weight differently. Rust Strength records which machine each set was performed on and rounds to that machine's own increment, so a session in a hotel gym does not corrupt what it knows about your home gym.
WHAT YOU GET
Autoregulated weight suggestions after every set, with a plain-English reason for each one.
Estimated one-rep max per exercise, updated as you train.
Sets grouped by exercise, so five sets of bench read as one block.
Workout presets — save "Push Day 1" once and start it pre-loaded with every exercise.
A workout generator that builds a session from the equipment you actually have, prioritising the muscles you have not trained this week.
A live workout timer, plus totals for time, volume, reps and sets.
Activity tracking for runs, sports and cardio machines, timed live or entered by hand.
A calendar for planning sessions ahead, logging rest days, and reviewing what you have done.
A body chart showing which muscle groups you have and have not trained this week.
A rest timer between sets, set to whatever length you want, that starts on its own when you save a set and can alert you when rest is over, even with your phone locked.
Tiered trophies across nine ranks, from Wood to Legend, for the main lifts, calisthenics, and lifetime weight moved.
XP and levels earned from the training you log, unlocking badges as you climb.
A feed of your friends' recent sessions that you can react to, and profiles showing their streaks, levels and progress.
DESIGNED TO ASK FOR LITTLE
No ads. No analytics. No tracking. No third-party advertising SDKs. Rust Strength asks for an email address and a password so your training syncs to your devices, and collects nothing it does not need to run. Your bodyweight is optional. Friends see a summary of a session, never the individual sets, and you can switch feed sharing off entirely. You can export everything you have logged, and delete your account and all its data from inside the app at any time.
IMPORTANT
Rust Strength is a training log, not medical or professional coaching advice. It suggests weights from the numbers you give it and knows nothing about your health, injuries, or experience. Warm up, use your own judgement, and stop if something hurts. Talk to a doctor before starting a new training programme.
Privacy Policy: https://lindellrhett-gif.github.io/rust-strength/privacy.html
Terms of Service: https://lindellrhett-gif.github.io/rust-strength/terms.html
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The developer, RHETT JOHN LINDELL, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Linked to You
The following data may be collected and linked to your identity:
- Health & Fitness
- Contact Info
- User Content
- Identifiers
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- RHETT JOHN LINDELL
- Size
- 40.1 MB
- Category
- Health & Fitness
- Compatibility
Requires iOS 16.4 or later.
- iPhone
Requires iOS 16.4 or later. - Mac
Requires macOS 12.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later.
- iPhone
- Languages
- English
- Age Rating
13+
- 13+
- Frequent
Contests
Contains
User-Generated Content
Health or Wellness Topics
Social Media
- Copyright
- © 2026 Rhett Lindell