Sonar Ruler vs CMCalc
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Sonar Ruler
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.
- Sonic distance measurement
- Up to 60 feet range
- Selectable units (feet, inches, meters)
- Custom saved settings
- Educational sonar demonstration
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Sonar Ruler is a winner in the Best App Ever Awards - "Most innovative use of iPhone hardware" category! The Amazing New Sonar Ruler is an experimental app that uses echoes to measure distances with your iPhone! * It uses the same principles that dolphins use to find food! * It sends a short pulse from the speaker and measures how long that pulse takes to bounce off of something and return to the phone. It then estimates how far away you are. >> Impress your friends with what this unique app can accomplish using only an iphone! << Ϟ GIZMODO.com: "that's a damned neat trick for a phone to be able to do." Features: * Sonic distance measurement up to 60 feet * Set Units to feet, inches, or meters * Custom saved settings for measuring in different environments If you're a teacher, this app is a great way to teach students the principles of sonar, and how sound propagates through air. ** Watch a demo video here: http://bit.ly/sonarvideo ** German/Japanese subtitles here: http://bit.ly/sonarvid Enjoy! Follow us on twitter @laanlabs *This is an experimental app, although it can be quite accurate, any measurements taken should be verified before using them. Note: Use with iPads requires some adjustment to the chirp boundaries
CMCalc
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.
- 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
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The CMCalc application is a replica of the Casio CM-100 Computer Math Calc solar powered calculator that was sold in the mid 1980’s. It performs simple decimal arithmetic and basic binary conversions (decimal - binary - octal - hexadecimal) and binary logic functions. While it is a standard infix calculator, it supports operator grouping with parentheses. For hexadecimal calculations, the input keys include A through F. CMCalc application performs all the same functions as the calculator, and has the same look as the original. There are a couple features that were not conceivable in the 1980’s on a calculator … such as the ability to copy and paste the results or the entered function, and a landscape mode for devices with 4 inch or larger screens. The face of the calculator can be viewed in two modes including a traditional application style, and a photo replica of the original calculator face.
Screenshots
Verdict
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.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
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.
| Parameter | Sonar Ruler | CMCalc |
|---|---|---|
| Price | $0.99 | Free — better |
| Rating | 2.7 (3 ratings) | 4.6 (7 ratings) — better |
| Positive reviews | 43.5% of reviews | 75.0% of reviews — better |
| Number of ratings | 3 | 7 — better |
| Update frequency | Every 94 months | Every 45 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Free — better |
| Devices | iPhone, iPad, iPod — better | iPhone, iPod |
| Requires iOS | 8.1 — better | 12.0 |
| Further details — not scored | ||
| Size | 13 MB | 4 MB |
| Age rating | 4+ | 4+ |
| Developer | Laan Labs | William David |
Customer experience
Sonar Ruler
CMCalc
Bugs and requests
Sonar Ruler
Reported bugs
10 issues- 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
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- Broken help video URL
- Measurements lock at same distance regardless of location
- Metric mode produces incorrect readings
- Incompatible with iPhone 4S, 5, and first-generation devices
- Inconsistent performance across different iPhone models
Requested features
11 requests- 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)
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- Larger, easier-to-manipulate sliders
- iPod Touch compatibility
- Automatic zoom functionality for measurements
- Visual indicator for when to use short vs long distance mode
- Better help video and documentation
- Accessibility features for blind users
CMCalc
Not enough reviews yet to summarise bugs or requests.
In-app purchases
Sonar Ruler
No in-app purchases
CMCalc
No in-app purchases









