# Sonar Ruler vs CMCalc

The clearest difference is price: CMCalc at Free against Sonar Ruler's $0.99. CMCalc also leads on rating (4.6 vs 2.7) and review sentiment (75% vs 43%). Sonar Ruler's advantage is iOS requirement (8.1 vs 12.0). On ratings volume, ads, in-app purchases and device support there is nothing between them.

CMCalc is free to download; Sonar Ruler costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

CMCalc holds the better App Store score, 4.6 against 2.7. Both are backed by a comparable volume of ratings — 3 and 7 respectively. Written reviews point the same way: 43% of Sonar Ruler's written reviews are positive against 75% of CMCalc's.

Sonar Ruler ships an update every 94 months, CMCalc every 45 months. The most recent releases landed on October 31, 2026 and October 29, 2026 respectively.

## The numbers

| Metric | Sonar Ruler | CMCalc |
| --- | --- | --- |
| Price | $0.99 | **Free** |
| Rating | [2.7 (3 ratings)](https://appshunter.io/ios/app/sonar-ruler/id324621243/reviews) | **[4.6 (7 ratings)](https://appshunter.io/ios/app/cmcalc/id974432836/reviews)** |
| Number of ratings | 3 | **7** |
| Positive reviews | 43.5% of reviews | **75.0% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 94 months | **Every 45 months** |
| Monetization | Paid | **Free** |
| Size | 13 MB | 4 MB |
| Requires iOS | **8.1** | 12.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Laan Labs](https://appshunter.io/developer/310916919) | [William David](https://appshunter.io/developer/974432835) |

## What reviewers say

### Sonar Ruler

[App page](https://appshunter.io/ios/app/sonar-ruler/id324621243)

This experimental app uses your iPhone's speaker to send out sonic pulses and measures the echo to estimate distances up to 60 feet. It's a fun and innovative way to explore sonar principles, perfect for educational purposes or impressing friends with unique iPhone capabilities.

**Highlights:** Sonic distance measurement, Up to 60 feet range, Selectable units (feet, inches, meters), Custom saved settings, Educational sonar demonstration

**Features:** Vision Pro support

**In-app purchases:** none

**What reviewers like**

- 💡 Innovative sonar technology using iPhone hardware
- 🎯 Accurate measurements when used correctly (±0.5-1 inch)
- 📚 Educational value for learning sound principles
- 🎮 Fun novelty app for impressing friends
- ⚙️ Customizable settings for different environments

**What reviewers complain about**

- 🐛 Crashes immediately on many iPhone models
- ❌ Doesn't work on older iPhone generations (iPhone 4, 4S, 5)
- 🔊 Highly sensitive to background noise and interference
- 😕 Steep learning curve and unintuitive interface
- ⚠️ Inconsistent and unreliable measurements

**Reported bugs**

- App crashes within 3 seconds of opening on iPhone 6 and older models
- Won't open on iOS 8.4 and later versions
- No chirping sound emitted on some devices
- Feedback loop and screaming noise on certain hardware
- Phone locks up requiring hard restart

**Requested features**

- Room mapping by rotating phone in circle
- Vertical distance measurement capability
- Better ambient noise filtering
- Clearer, more intuitive user interface
- Optimized default settings (frequency, filter, chirp)


### CMCalc

[App page](https://appshunter.io/ios/app/cmcalc/id974432836)

This app emulates a classic 1980s computer math calculator, offering decimal arithmetic, binary conversions, and logic functions. It supports parentheses for complex calculations and includes modern features like copy/paste and landscape mode.

**Highlights:** Decimal arithmetic, Binary conversions (decimal, binary, octal, hexadecimal), Binary logic functions, Operator grouping with parentheses, Hexadecimal input (A-F), Copy and paste results/functions, Landscape mode

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Sonar Ruler free?

Sonar Ruler costs $0.99, with no in-app purchases.

### Is CMCalc free?

CMCalc is free to download, with no in-app purchases.

### Which has better reviews, Sonar Ruler or CMCalc?

CMCalc is rated higher. Sonar Ruler averages 2.7 out of 5 from 3 ratings, while CMCalc averages 4.6 from 7 ratings.

### Do Sonar Ruler or CMCalc have ads?

Neither Sonar Ruler nor CMCalc shows ads.

### Which is updated more often, Sonar Ruler or CMCalc?

Sonar Ruler ships an update every 94 months, and CMCalc every 45 months. Most recently, Sonar Ruler was updated on October 31, 2026 and CMCalc on October 29, 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.*