The app sets the weight for your next set
Log a set to recalculate your next weight and reps.
- Estimated 1RM (e1RM) An estimate of the most weight you could lift once
- RIR (reps in reserve) How many more reps you could have done when you stopped
- Deload A planned recovery week, one light week after several weeks of training
- Set-by-set target vs. actual
Logging is free. Coaching is Pro. 14-day free trial for first-time subscribers.
GYMKC is on the App Store for iPhone and iPad.
During your workout
Log a set and your next set changes
You see why it's that weight
If you have reps left, the weight goes up. If it was a grind, it comes down.
Rest time also gets longer or shorter depending on how hard your last set was.
Your target and what you actually did sit side by side on one line, so you can see set by set whether you did what you planned.
Voice coaching talks you through it, and a rest alert goes off even when your screen is off.
You can also see where your next progress will come from.
The workout card shows whether it's time to add weight, or to add reps or sets.
Your weights and sets are set by the calculation engine inside the app.
It calculates straight from your logs, so it works the same even in a basement gym with no signal.
The same logs always give the same prescription, and it never makes up a weight you don't have.
See whether you're building strength or size
Set your goal balance between strength and hypertrophy, and the app checks every week whether you're keeping it.
If you drift off, it points out what to add.
When a muscle group's weekly volume falls short of the recommended minimum, it suggests efficient exercises for that area.
Exercises that stop improving are marked as a plateau.
It doesn't analyze once and stop.
Analysis builds up with every workout and every week, and what builds up goes into your next prescription.
See which muscles you're working
The library of 7,630 exercises comes with 3D form demos and muscle maps.
You don't need another app to check your form.
See a machine you don't recognize at the gym? Take a photo and the app tells you what it is and how to use it, and you can add it straight to the workout you're doing.
No equipment at home? You can still build a workout with bodyweight exercises.
Builds week by week, and knows when to back off
Workout days and sets are planned to fit your goal.
So you don't just keep pushing, deload weeks are built in.
If you're new, one is suggested only when fatigue signals are high.
Already have a routine? On Pro, take a photo and bring it over as is.
A screenshot from another app, a spreadsheet, or a handwritten page all work.
Register the equipment you have, and the app only builds routines you can do with it.
Save your gym and your home separately to train differently in each location.
If you have both barbells and dumbbells, it picks the one you prefer first.
Short on time? Tap "Short" to start a version with just the essentials.
Set a workout length target, and days that would run long get trimmed for you.
It checks your left-right balance too
If you're right-handed, your right arm often grows first.
Logs that give both sides the same target can't show that difference.
Choose the harder side after your last set.
Repeated differences lead to check sets. View changes in Stats.
For exercises with a weight in each hand, the app adds 1 check set with the same weight.
Move both arms together. Stop when either side cannot do another rep, then log which side reached its limit first and the other side's remaining reps.
The set stays in your log and is excluded when setting your next weight.
How side checks work
Beginners do not get check sets. Rechecks start after 28 days.
Measured gaps use only one-arm checks with the starting side logged. Alternate starting sides. The same side must be at least 15% behind for 3 checks in a row.
Two-arm checks only note which side reached its limit first. Your weight stays the same.
Weaker-side-first guidance requires Pro, automatic prescription, an advanced profile, and at least 12 sessions of that exercise.
You just finished your last set. Try it yourself.
Evidence
Every piece of advice has a source
This is the knowledge the trainer draws on when it explains "why."
We analyze public content from evidence-based training experts in Korea and abroad,
review the evidence behind each claim, remove claims that have been debunked, and mark the ones that are contested.
That way, advice without evidence doesn't get passed along as is.
The numbers used in prescriptions are held to the same standard. For values like when to add a set or how much to cut back after a break,
we look for evidence in peer-reviewed papers and in this knowledge and record it for each item.
When the evidence is weak, we record it as weak, and when a paper disagrees with our call, we record that too and review it again.
This knowledge doesn't replace prescriptions.
The app's calculation engine sets your weights and sets from your logs, and the trainer uses the knowledge base to explain "why."
GYMKC has no affiliation, sponsorship, or endorsement relationship with any creator or brand mentioned.
"Verified" and "Contested" ratings indicate plausibility and do not replace medical advice.
Together
Train together, without ads
- You don't have to train aloneCreate a crew with an invite code to share coach reviews, weekly challenges, and routines.
- No adsOur revenue comes only from subscriptions.
You can export your workout logs to a file anytime.
Questions
Common questions before you start
Can beginners use it?
Yes. If you're new, your target leaves 2 reps in reserve instead of taking you to failure, and when the weight is adjusted during a workout, it never changes more than 5% at a time. Your first weights are set conservatively based on your sex and age, and once you've logged some workouts, your own logs set the next weight.
I already do personal training. Can I use GYMKC too?
Yes. Hands-on coaching is still the most accurate way to fix your form. GYMKC carries your logs and your next weights through the days between sessions. Create a crew to train alongside your coach, and your coach can see your logs only if you allow it.
Can I use it with just my phone, without a smartwatch?
Yes. Logging, the rest timer, and next-set calculations all work with just your phone. Voice coaching plays from your phone too. Watch coaching and outdoor GPS tracking are Pro plan features. Without a watch, your phone tracks GPS.
Will I get a custom routine if I work out at home with dumbbells or just my bodyweight?
Yes. Choose the equipment you have, and your routine is built only from exercises you can do with it. For dumbbells, the next step comes from your list of dumbbell weights. For bodyweight exercises, reps go up first, and once you reach the top of the range, the app suggests adding weight.
Can I use it while pregnant or after giving birth?
If you've talked with your healthcare provider and been cleared to exercise, you can turn on pregnancy or postpartum adjustments during setup or in Settings. They swap out exercises done lying on your back, moves that load your core heavily and high-impact moves, and prescribe with more reps in reserve. This information needs separate consent and is never sent to AI.
Is it really free? Do I need to enter payment info?
You don't need payment info to sign up and log workouts. Logging is free, and real-time coaching is the Pro plan. Pro is an App Store subscription, and Apple accounts subscribing for the first time get a 14-day free trial. When the trial ends, it renews automatically at the regular price. If you cancel in your App Store account settings at least 24 hours before the trial ends, you won't be charged, and everything you logged on Free stays.
Who sets the weight? Is it AI?
The calculation engine inside the app sets it from your logs, and it works the same without an internet connection. AI explains why it's that weight and helps you build routines. We've written up how the calculation works. See how it works
Pricing
Logging is free, coaching is Pro
Real-time coaching, which recalculates your next weight the moment you log a set and shows why, is the Pro plan.
$0
No time limit- Log and edit workouts, with no time limit on storage
- Create routines and edit targets: set weight, reps, and sets yourself
- Deload weeks planned in your routine · a lighter recovery week
- Library of 7,630 exercises · 3D form demos
- Rest timer · Workout reminders
- Crews · Feed · Workout cards · Apple Health sync
- A taste of AI features (limited uses)
$59.99
per year · That's $4.99/month- Next weight and reps recalculated after every set, with the reason
- Rest that reads how hard your last set was and adjusts itself
- Suggests a drop set when you have reps left, and a variation when you plateau
- Left-right balance check-ins · Check sets · Trends
- This week's results become next week's targets, with weight increases and recovery weeks matched to your check-ins
- Today's workout adjusted to your condition, pain, and time
- Watch sync (Apple Watch, app only)
- Outdoor GPS tracking (running · walking · cycling)
- AI trainer chat 10 times a day · Analysis and briefing for every workout · AI routines 10 times a month · Equipment scans 15 times a month · Weekly report
- At AI limits, analysis and chat switch to simple mode. Other quotas reset the next day, week or month. Logging and crews have no cap (Terms, Article 8).
Pro starts with a 14-day free trial for Apple accounts subscribing for the first time.
When the trial ends, it renews automatically at the regular price for the cycle you chose.
If you cancel in your App Store account settings at least 24 hours before the trial ends, you won't be charged.
Payments and cancellation are managed in the App Store.
Your logs stay. Coaching starts with your next set.
Prices shown are for the US App Store. In Canada, Australia, New Zealand, and Singapore, the App Store shows the price in your local currency.
Start logging today's workout
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