# ClinicalKey vs Opioid Conversion Calculator

The clearest difference is in-app purchases: ClinicalKey at none against Opioid Conversion Calculator's 3. Opioid Conversion Calculator's advantage is review sentiment (38% vs 9%) and iOS requirement (13.0 vs 15.0). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Opioid Conversion Calculator sells 3 in-app purchases, starting at $3.99 per month. ClinicalKey asks for nothing beyond the download.

ClinicalKey ships an update every 5 weeks, Opioid Conversion Calculator every 6 weeks. The most recent releases landed on October 16, 2026 and October 9, 2026 respectively.

## The numbers

| Metric | ClinicalKey | Opioid Conversion Calculator |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[3.7 (17 ratings)](https://appshunter.io/ios/app/opioid-conversion-calculator/id6446010375/reviews)** |
| Number of ratings | — | **17** |
| Positive reviews | 8.8% of reviews | **37.5% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 5 weeks** | Every 6 weeks |
| Monetization | Subscription | **Free with in-app purchases** |
| Size | 55 MB | 76 MB |
| Requires iOS | 15.0 | **13.0** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 12+ | 17+ |
| Developer | [Elsevier Inc.](https://appshunter.io/developer/367031326) | [Ayrial Beall](https://appshunter.io/developer/1735693360) |

## What reviewers say

### ClinicalKey

[App page](https://appshunter.io/ios/app/clinicalkey/id1041998175)

This app provides medical professionals with instant access to a vast library of clinical knowledge, including synoptic content and in-depth reference materials. It helps users stay updated on medical advancements, confirm diagnoses, and advance their research skills, all while offering CME/MOC/CE credits.

**Highlights:** Access to 30+ medical specialties, Synoptic content for quick answers, Full-text reference books and journals, Mobile-optimized medical calculators, Earn CME/MOC/CE credits, Intuitive search functionality

**In-app purchases:** none

**What reviewers like**

- 📚 High-quality, evidence-based clinical content
- 🎯 Intuitive interface and quick reference format
- 🔍 Similar functionality to website version
- 👍 Browse feature restoration appreciated by users

**What reviewers complain about**

- 🔓 Constant forced logout issues
- 🔐 Institutional login authentication failures
- ⏳ App freezes and perpetual loading screens
- 🚫 Missing textbook access in app vs website
- 📵 Frequent crashes and force closures

**Reported bugs**

- App stuck on loading screen after initial login
- Forced logout when closing or minimizing app
- Institutional login not working despite web access
- App crashes during search queries
- OpenAthens authentication failures

**Requested features**

- PDF download capability within the app
- Favorite/bookmark textbooks and articles
- Landscape mode support for iPad
- Find-on-page text search function
- Automatic session persistence and page memory


### Opioid Conversion Calculator

[App page](https://appshunter.io/ios/app/opioid-conversion-calculator/id6446010375)

This medical app simplifies complex opioid conversion tasks for healthcare professionals. It offers extensive drug coverage, a visual safety indicator for dosages, and breakthrough dosing calculations. Available in multiple languages, it ensures accurate and safe pain management.

**Highlights:** Extensive drug coverage, Visual safety indicator, Breakthrough dosing calculations, Formulation conversions, Up-to-date pharmaceutical formulary, Multilingual support

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

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Monthly Pro Access | $3.99 | per month |
| Pro Access | $19.99 | per year |
| Lifetime Pro Access | $79.99 | one-time |


## Frequently asked questions

### Is ClinicalKey free?

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

### Is Opioid Conversion Calculator free?

Opioid Conversion Calculator is free to download, with in-app purchases available.

### Do ClinicalKey or Opioid Conversion Calculator have ads?

Neither ClinicalKey nor Opioid Conversion Calculator shows ads.

### Which is updated more often, ClinicalKey or Opioid Conversion Calculator?

ClinicalKey ships an update every 5 weeks, and Opioid Conversion Calculator every 6 weeks. Most recently, ClinicalKey was updated on October 16, 2026 and Opioid Conversion Calculator on October 9, 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.*