531 Strength vs Simple One
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
531 Strength
This app simplifies tracking your progress on the 5/3/1 strength training program. It calculates and displays weights, reps, and sets based on your one-rep max, allowing you to easily plan and execute your workouts. Rounding options help match available gym plates.
- Calculate 5/3/1 weights
- Track 1RM for exercises
- View cycle step weights
- Round weights to available plates
- Full overview of weights, reps, sets
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Makes it quick and easy to get a full overview of all weights, reps and sets based off your 1RM when you’re following the 5/3/1 program. - Save your current 1 RM for each of the four exercises - View calculated weights for each step in the cycle - Round the weight to match the plates you have available This app is made for people who are familiar with the structure of the 5/3/1 program and who needs simple access to the calculated weights for each exercise.
Simple One
This app helps you accurately determine your one-rep max (1RM) using multiple proven formulas. It provides reliable estimates to help you choose the right weights for your training, ensuring safer and more effective strength progression.
- Accurate one-rep max estimates
- Multiple proven calculation formulas
- Determine training weights
- Fast and simple interface
- Distraction-free design
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Stop guessing your max. Train with confidence. Simple One Rep Max Calculator helps you understand how strong you really are — so every workout has a purpose. By calculating your one-rep max using multiple proven formulas, you get realistic numbers you can trust, not just a single estimate. Know your limits, choose the right weights, and progress safely — whether you’re pushing for new PRs or building strength over time. Why you’ll love it • Clear and reliable max lift estimates • Multiple formulas for better confidence • Training weights at the right intensity • Fast, simple, and distraction-free Less guessing. Better progress.
Screenshots
Verdict
The clearest difference is price: 531 Strength at Free against Simple One's $0.99. 531 Strength also leads on review sentiment (94% vs 50%) and update cadence (every 2 months vs every 13 months). Simple One's advantage is in-app purchases (none vs 4) and ads (none vs shown). On 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
531 Strength is free to download; Simple One costs $0.99 up front. 531 Strength sells 4 one-off in-app purchases. Simple One asks for nothing beyond the download.
531 Strength holds the better App Store score, 4.9 against 4.5. That said, the two scores are not equally well evidenced: 531 Strength has 12K ratings behind it against 2, so its average is the more settled of the two. Written reviews point the same way: 94% of 531 Strength's written reviews are positive against 50% of Simple One's.
531 Strength ships an update every 2 months, Simple One every 13 months. The most recent releases landed on October 28, 2026 and October 20, 2026 respectively.
| Parameter | 531 Strength | Simple One |
|---|---|---|
| Price | Free — better | $0.99 |
| Rating | 4.9 (12K ratings) — better | 4.5 (2 ratings) |
| Positive reviews | 94.0% of reviews — better | 50.0% of reviews |
| Number of ratings | 12K — better | 2 |
| Update frequency | Every 2 months — better | Every 13 months |
| Ads | Yes | No — better |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases — better | Paid |
| Devices | iPhone, iPad — better | iPhone |
| Requires iOS | 18.0 | 16.0 — better |
| Further details — not scored | ||
| Size | 26 MB | 2 MB |
| Age rating | 4+ | 17+ |
| Developer | Henrik Jachobsen | Above AS |
Customer experience
531 Strength
Simple One
Bugs and requests
531 Strength
Reported bugs
2 issues- Rest timer stops when app is backgrounded
- Plate calculator not flexible enough
Requested features
4 requests- Ability to adjust training max separately from 1RM
- Option to track rep PRs and estimated 1RM
- Accessory exercise tracking and planning
- Sync progress across devices
Simple One
Not enough reviews yet to summarise bugs or requests.
In-app purchases
531 Strength
- Additional exercises$1.99
- Adjustable set$1.99
- Plate calculator$1.99
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- Progress log$6.99
Simple One
No in-app purchases
Questions
Is 531 Strength free?
Is Simple One free?
Which has better reviews, 531 Strength or Simple One?
Do 531 Strength or Simple One have ads?
Which is updated more often, 531 Strength or Simple One?
Other comparisons
