S2 vs Stacked
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
S2
This app helps you track and visualize your gym workout progress, encouraging progressive overload for weight loss or muscle gain. It offers a fast, intuitive interface with over 1000 exercises and a unique muscle fatigue heat map. No account is needed, and it integrates with HealthKit.
- Track and visualize workout progress
- Muscle fatigue heat map
- Create unlimited workout routines
- Encourages progressive overload
- 1000+ exercises
- Workout history review
- HealthKit integration
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S2 (Superior Self) is your ultimate workout companion, allowing you to track and visualize your workout progress. Whether you want to lose weight or gain muscle mass, S2 is an excellent tool to help you with progressive overload and beat the yesterday you. - Premium, beautiful workout app - No account registration is required - Fast and intuitive. No load times - View your muscle fatigue on a body heat map - Create unlimited workout routines - Encourages progressive overload - 1000+ exercises - Improved insights over time How does it work? Start by creating your workout routines in S2. Your first workout for any given routine will act as a baseline for the next workout, encouraging you to do more work by moving more mass. The technical term for this is called progressive overload, and it's the core principle behind any successful strength training. Between workouts (or during an ongoing workout) you can review your past performance by easily accessing your workout history. S2 integrates with HealthKit to register your workouts. Terms of use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/
Stacked
This application helps users plan and track weightlifting workouts to build muscle and strength. It offers a clean interface designed by weightlifters for weightlifters, with features for routine creation, progress tracking, and automatic plate calculations.
- Plan and track weightlifting workouts
- Create simple or complex routines
- Track personal records
- Automatic plate math
- Review past workout data
- Cloud data backup
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FINALLY! A 100% FREE WEIGHTLIFTING APP ACTUALLY WORTH USING! Whether you’re a beginner or an experienced weightlifter, Stacked will help you gain muscle and strength faster. With it, you can easily and effectively plan and track your weightlifting workouts and fitness goals. And unlike most other weightlifting apps, Stacked isn’t ugly, unwieldy, unintuitive, and cluttered with unimportant features that you’ll never use. Instead, it’s clean, elegant, and streamlined because it was built by weightlifters for weightlifters. And better still—Stacked is 100% free with no restrictions or hidden upgrade fees. Here are just a few examples of why Stacked is special . . . Create simple or complex workout routines Choose Imperial or metric measurements Set weight and rep goals for exercises Track personal records for all exercises Change workouts on the fly by adding or removing exercises and sets Automatically do plate math (always know how to load the bar correctly!) Review past workouts including exercises, sets, notes, duration, volume, and more Automatically back up your data in the cloud And more! So, if you’re ready to get more out of your training by successfully planning, tracking, and analyzing your workouts, download Stacked now and start your journey today!
Screenshots
Verdict
The clearest difference is rating: Stacked at 4.6 against S2's 4.1. Stacked also leads on in-app purchases (none vs 2) and review sentiment (66% vs 41%). S2's advantage is update cadence (fortnightly vs every 6 weeks). On price, ads, monetization model and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. S2 sells 2 in-app purchases, starting at $22.99 per year. Stacked asks for nothing beyond the download.
Stacked holds the better App Store score, 4.6 against 4.1. That said, the two scores are not equally well evidenced: Stacked has 1.6K ratings behind it against 126, so its average is the more settled of the two. Written reviews point the same way: 41% of S2's written reviews are positive against 66% of Stacked's.
S2 ships an update fortnightly, Stacked every 6 weeks. The most recent releases landed on October 12, 2026 and October 17, 2026 respectively.
| Parameter | S2 | Stacked |
|---|---|---|
| Price | Free | Free |
| Rating | 4.1 (126 ratings) | 4.6 (1.6K ratings) — better |
| Positive reviews | 41.3% of reviews | 65.8% of reviews — better |
| Number of ratings | 126 | 1.6K — better |
| Update frequency | Fortnightly — better | Every 6 weeks |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Devices | iPhone | iPhone, iPod — better |
| Requires iOS | 16.0 | 11.0 — better |
| Further details — not scored | ||
| Size | 9 MB | 110 MB |
| Age rating | 12+ | 4+ |
| Developer | Formbound AB | M4L, Inc. |
Customer experience
S2
Stacked
Bugs and requests
S2
Not enough reviews yet to summarise bugs or requests.
Stacked
Reported bugs
5 issues- Workout data not saving properly
- Inability to log certain weight increments
- Frequent crashes and freezes
- Sync issues causing loss of workout history
- Incorrect default weight display
Requested features
8 requests- Ability to edit and delete workouts
- More customization options for workouts and routines
- Integration with Apple Health and other fitness apps
- Exercise demonstration videos or GIFs
- Superset and triset functionality
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- Ability to set custom rest periods
- Warm-up set planning and tracking
- Improved data syncing and backup
In-app purchases
S2
- S2 Yearly$22.991 Year
- Strongly Pro$4.99
Stacked
No in-app purchases








