# 1RM Calculator vs CK Strength

The clearest difference is update cadence: CK Strength at every 6 weeks against 1RM Calculator's every 4 months. On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. 1RM Calculator sells 3 in-app purchases, starting at $1.99 per month and CK Strength sells 1 in-app purchase, starting at $219.00 per month. Whichever you choose, the download price is not the number that matters.

1RM Calculator ships an update every 4 months, CK Strength every 6 weeks. The most recent releases landed on October 30, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | 1RM Calculator | CK Strength |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.9 (128 ratings)](https://appshunter.io/ios/app/1rm-calculator/id1566775126/reviews)** | — |
| Number of ratings | **128** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 6 weeks** |
| Monetization | Free with in-app purchases | — |
| Size | 28 MB | 50 MB |
| Requires iOS | 15.0 | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [Yuri Koshiishi](https://appshunter.io/developer/1566775128) | [CK Strength + Performance Strategies LLC](https://appshunter.io/developer/1738495727) |

## What reviewers say

### 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 |


### CK Strength

[App page](https://appshunter.io/ios/app/ck-strength/id6480217738)

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Custom Ongoing Coaching | $219.00 | per month |


## Frequently asked questions

### Is 1RM Calculator free?

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

### Is CK Strength free?

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

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

Neither 1RM Calculator nor CK Strength shows ads.

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

1RM Calculator ships an update every 4 months, and CK Strength every 6 weeks. Most recently, 1RM Calculator was updated on October 30, 2026 and CK Strength on October 25, 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.*