# Calculate by QxMD vs AO Surgery Reference

The clearest difference is ads: AO Surgery Reference at none against Calculate by QxMD's shown. AO Surgery Reference also leads on monetization model (free vs free with in-app purchases) and iOS requirement (13.0 vs 16.0). Calculate by QxMD's advantage is rating (4.8 vs 4.4) and ratings volume (5.1K vs 14). On price, review sentiment, in-app purchases and device support there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Calculate by QxMD holds the better App Store score, 4.8 against 4.4. That said, the two scores are not equally well evidenced: Calculate by QxMD has 5.1K ratings behind it against 14, so its average is the more settled of the two. Written reviews split almost evenly too, at 86% and 86% positive.

Calculate by QxMD ships an update every 6 weeks, AO Surgery Reference every 6 months. The most recent releases landed on November 1, 2026 and October 23, 2026 respectively.

## The numbers

| Metric | Calculate by QxMD | AO Surgery Reference |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.8 (5.1K ratings)](https://appshunter.io/ios/app/calculate-by-qxmd/id361811483/reviews)** | [4.4 (14 ratings)](https://appshunter.io/ios/app/ao-surgery-reference/id403961165/reviews) |
| Number of ratings | **5.1K** | 14 |
| Positive reviews | **86.5% of reviews** | 85.8% of reviews |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | **Every 6 weeks** | Every 6 months |
| Monetization | Free with in-app purchases | **Free** |
| Size | 118 MB | 1 MB |
| Requires iOS | 16.0 | **13.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 17+ | 17+ |
| Developer | [WebMD](https://appshunter.io/developer/295076332) | [AO Foundation](https://appshunter.io/developer/399757056) |

## What reviewers say

### Calculate by QxMD

[App page](https://appshunter.io/ios/app/calculate-by-qxmd/id361811483)

This clinical calculator and decision support tool offers over 200 medical calculators and tools for diagnosis, treatment, and prognosis. It adapts to your practice and provides detailed references, integrating with PubMed and Read by QxMD.

**Highlights:** Over 200 medical calculators, Clinical decision support tools, Cardiology, internal medicine, and more, Knowledge translation from research, Question Flow technology, PubMed & Read integration, SI and Imperial units

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

**In-app purchases:** none

**What reviewers like**

- ⭐ Excellent app
- 📋 Comprehensive set of calculators
- 🔍 Helpful references and explanations
- 🔧 Useful for daily practice
- 🧠 Great for students and trainees

**What reviewers complain about**

- 🐛 App freezes or crashes
- 🔍 Some calculators not working
- 🔑 Repeated login requests
- 🔍 Outdated or missing features
- 🚫 Ads can be intrusive

**Reported bugs**

- App freezes when using multiple calculators
- Unable to add items to favorites list
- Unable to see calculation results after input
- App crashes on startup without internet connection
- Landscape mode not working on iPad

**Requested features**

- Dark mode option
- Ability to save/favorite frequently used calculators
- Integration with electronic health records
- Metric to imperial unit conversion
- More specialized calculators (e.g., opioid equivalence, pediatric BP)


### AO Surgery Reference

[App page](https://appshunter.io/ios/app/ao-surgery-reference/id403961165)

Access a comprehensive online repository of surgical knowledge for fracture management. It provides detailed guidance on diagnosis, treatment, and aftercare for numerous fracture types, supported by extensive illustrations and expert review.

**Highlights:** 353 fracture types covered, 172 surgical approaches, 1222 surgical procedures, Over 30,000 illustrations, Feline, canine, and equine fracture care, Powerful search function

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

**In-app purchases:** none


## Frequently asked questions

### Is Calculate by QxMD free?

Calculate by QxMD is free to download, with no in-app purchases.

### Is AO Surgery Reference free?

AO Surgery Reference is free to download, with no in-app purchases.

### Which has better reviews, Calculate by QxMD or AO Surgery Reference?

Calculate by QxMD is rated higher. Calculate by QxMD averages 4.8 out of 5 from 5.1K ratings, while AO Surgery Reference averages 4.4 from 14 ratings.

### Do Calculate by QxMD or AO Surgery Reference have ads?

Calculate by QxMD shows ads; AO Surgery Reference does not.

### Which is updated more often, Calculate by QxMD or AO Surgery Reference?

Calculate by QxMD ships an update every 6 weeks, and AO Surgery Reference every 6 months. Most recently, Calculate by QxMD was updated on November 1, 2026 and AO Surgery Reference on October 23, 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.*