# Ruler vs CPD Mastery

The clearest difference is ads: CPD Mastery at none against Ruler's shown. CPD Mastery also leads on update cadence (monthly vs every 5 months). On price, in-app purchases, device support and iOS requirement there is nothing between them.

Both are free to download. Ruler sells 1 one-off in-app purchase and CPD Mastery sells 1 in-app purchase, starting at $9.99 per month. Whichever you choose, the download price is not the number that matters.

Ruler ships an update every 5 months, CPD Mastery monthly. The most recent releases landed on October 13, 2026 and October 5, 2026 respectively.

## The numbers

| Metric | Ruler | CPD Mastery |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.7 (3 ratings)](https://appshunter.io/ios/app/ruler-scale-ruler/id919130707/reviews)** | — |
| Number of ratings | **3** | — |
| Positive reviews | 63.0% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | Every 5 months | **Monthly** |
| Monetization | Free with in-app purchases | — |
| Size | 4 MB | 40 MB |
| Requires iOS | **15.0** | 15.1 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [mitsunori oishi](https://appshunter.io/developer/905649994) | [Craig Bartlett](https://appshunter.io/developer/1791147194) |

## What reviewers say

### Ruler

[App page](https://appshunter.io/ios/app/ruler-scale-ruler/id919130707)

This app displays various measurement scales for length, including meters and inches. It allows users to set magnification ratios and reduced scales for different applications. Users can calibrate the ruler and adjust PPI settings for accurate measurements.

**Highlights:** Display various measurement scales, Set magnification ratios, Set reduced scales, Measure in meters and inches, Free mode for custom scales, Calibration for accuracy, PPI setting

**Features:** macOS Compatibility, Family Sharing

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Hide Ads | $0.99 | one-time |


### CPD Mastery

[App page](https://appshunter.io/ios/app/cpd-mastery/id6740707032)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| CPD Mastery Premium | $9.99 | per month |


## Frequently asked questions

### Is Ruler free?

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

### Is CPD Mastery free?

CPD Mastery is free to download, with in-app purchases available.

### Do Ruler or CPD Mastery have ads?

Ruler shows ads; CPD Mastery does not.

### Which is updated more often, Ruler or CPD Mastery?

Ruler ships an update every 5 months, and CPD Mastery monthly. Most recently, Ruler was updated on October 13, 2026 and CPD Mastery on October 5, 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.*