# 1RM Calculator vs 531 Strength

The clearest difference is review sentiment: 531 Strength at 94% against 1RM Calculator's 37%. 531 Strength also leads on rating (4.9 vs 4.5) and ratings volume (12K vs 222). 1RM Calculator's advantage is ads (none vs shown) and update cadence (every 3 weeks vs every 2 months). On price, in-app purchases, monetization model and device support there is nothing between them.

Both are free to download. 1RM Calculator sells 1 one-off in-app purchase and 531 Strength sells 4 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

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 222, so its average is the more settled of the two. Written reviews point the same way: 37% of 1RM Calculator's written reviews are positive against 94% of 531 Strength's.

1RM Calculator ships an update every 3 weeks, 531 Strength every 2 months. The most recent releases landed on October 23, 2026 and November 1, 2026 respectively.

## The numbers

| Metric | 1RM Calculator | 531 Strength |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.5 (222 ratings)](https://appshunter.io/ios/app/1rm-calculator-one-rep-max/id681279192/reviews) | **[4.9 (12K ratings)](https://appshunter.io/ios/app/531-strength/id1062989244/reviews)** |
| Number of ratings | 222 | **12K** |
| Positive reviews | 36.8% of reviews | **94.0% of reviews** |
| In-app purchases | Yes | Yes |
| Ads | **No** | Yes |
| Update frequency | **Every 3 weeks** | Every 2 months |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 20 MB | 26 MB |
| Requires iOS | **12.1** | 18.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [David Bai](https://appshunter.io/developer/609405595) | [Henrik Jachobsen](https://appshunter.io/developer/497731838) |

## What reviewers say

### 1RM Calculator

[App page](https://appshunter.io/ios/app/1rm-calculator-one-rep-max/id681279192)

Estimate your maximum weight lifted for a single repetition. Input your successful lifts and reps to gauge strength, compare progress, and plan future training. Offers advanced features for detailed tracking and analysis.

**Highlights:** Estimate 1-rep max, Track lift history and progress, Historical chart and list views, Multiple estimation formulas, Calculate multiple rep maxes, Switch between lbs and kgs, View percentages of 1-rep max

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Upgrade | $1.99 | one-time |

**What reviewers like**

- 👍 Simple and easy to use
- 🚀 Calculates 1 rep max quickly
- 💡 Helps figure out percentages
- 👍 Good for tracking routines
- 👍 Clean design

**What reviewers complain about**

- 🐛 Pro version not working
- 🐛 Paid features inaccessible
- 🐛 App crashes after upgrade
- 🐛 UI needs improvement
- 🐛 Missing features

**Reported bugs**

- Pro not working after purchase
- Paid upgrade not granting access
- App crashes after upgrade
- Feedback email link broken
- + button crashes app

**Requested features**

- Ability to re-arrange exercises
- Ability to re-name exercises
- Ability to delete exercises
- See all trend lines on one graph
- Track more than one set per day


### 531 Strength

[App page](https://appshunter.io/ios/app/531-strength/id1062989244)

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.

**Highlights:** Calculate 5/3/1 weights, Track 1RM for exercises, View cycle step weights, Round weights to available plates, Full overview of weights, reps, sets

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Additional exercises | $1.99 | one-time |
| Adjustable set | $1.99 | one-time |
| Plate calculator | $1.99 | one-time |
| Progress log | $6.99 | one-time |

**What reviewers like**

- 🚀 Simple and efficient
- 👍 Intuitive interface
- 💪 Helps with strength gains
- 🔧 Customizable features
- ⏱️ Convenient timer

**What reviewers complain about**

- 🔢 Inaccurate percentage calculations
- 🗓️ Lack of ability to plan future workouts
- 📋 Limited exercise tracking
- 💰 Paid features not worth the cost

**Reported bugs**

- Rest timer stops when app is backgrounded
- Plate calculator not flexible enough

**Requested features**

- 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


## Frequently asked questions

### Is 1RM Calculator free?

1RM Calculator is free to download, with in-app purchases available.

### Is 531 Strength free?

531 Strength is free to download, with in-app purchases available.

### Which has better reviews, 1RM Calculator or 531 Strength?

531 Strength is rated higher. 1RM Calculator averages 4.5 out of 5 from 222 ratings, while 531 Strength averages 4.9 from 12K ratings.

### Do 1RM Calculator or 531 Strength have ads?

531 Strength shows ads; 1RM Calculator does not.

### Which is updated more often, 1RM Calculator or 531 Strength?

1RM Calculator ships an update every 3 weeks, and 531 Strength every 2 months. Most recently, 1RM Calculator was updated on October 23, 2026 and 531 Strength on November 1, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*