# 531 Strength vs 1RM Calculator

The clearest difference is ads: 1RM Calculator at none against 531 Strength's shown. 1RM Calculator also leads on iOS requirement (15.0 vs 18.0). 531 Strength's advantage is ratings volume (12K vs 130) and update cadence (every 2 months vs every 4 months). On price, rating, review sentiment and in-app purchases there is nothing between them.

Both are free to download. 531 Strength sells 4 one-off in-app purchases and 1RM Calculator sells 3 in-app purchases, starting at $1.99 per month. Whichever you choose, the download price is not the number that matters.

On the App Store both sit at effectively the same score — 4.9 for 531 Strength against 4.9 for 1RM Calculator. That said, the two scores are not equally well evidenced: 531 Strength has 12K ratings behind it against 130, so its average is the more settled of the two. Written reviews are what separate them: 94% of 531 Strength's written reviews are positive against 100% of 1RM Calculator's.

531 Strength ships an update every 2 months, 1RM Calculator every 4 months. The most recent releases landed on November 8, 2026 and November 7, 2026 respectively.

## The numbers

| Metric | 531 Strength | 1RM Calculator |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.9 (12K ratings)](https://appshunter.io/ios/app/531-strength/id1062989244/reviews)** | [4.9 (130 ratings)](https://appshunter.io/ios/app/1rm-calculator/id1566775126/reviews) |
| Number of ratings | **12K** | 130 |
| Positive reviews | 94.0% of reviews | **100.0% of reviews** |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | **Every 2 months** | Every 4 months |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 26 MB | 28 MB |
| Requires iOS | 18.0 | **15.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Henrik Jachobsen](https://appshunter.io/developer/497731838) | [Yuri Koshiishi](https://appshunter.io/developer/1566775128) |

## What reviewers say

### 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


### 1RM Calculator

[App page](https://appshunter.io/ios/app/1rm-calculator/id1566775126)

Easily calculate your one-rep max (1RM) strength with this app. It supports RPE input and allows you to estimate rep maxes based on your 1RM. Track your progress by saving your 1RM history for different exercises.

**Highlights:** 1RM calculation with RPE, Rep max estimation, Save 1RM history, Customizable exercises, Dark theme

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 1 Rep Max Pro Monthly | $1.99 | per month |
| 1 Rep Max Pro Annual | $9.99 | per year |
| 1 Rep Max Pro Lifetime | $29.99 | one-time |


## Frequently asked questions

### Is 531 Strength free?

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

### Is 1RM Calculator free?

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

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

531 Strength is rated higher. 531 Strength averages 4.9 out of 5 from 12K ratings, while 1RM Calculator averages 4.9 from 130 ratings.

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

531 Strength shows ads; 1RM Calculator does not.

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

531 Strength ships an update every 2 months, and 1RM Calculator every 4 months. Most recently, 531 Strength was updated on November 8, 2026 and 1RM Calculator on November 7, 2026.

---

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