# DIAX vs Skeleton Study Guide

The clearest difference is price: Skeleton Study Guide at $6.99 against DIAX's $19.99. Skeleton Study Guide also leads on chart position (#195 vs unranked). DIAX's advantage is update cadence (every 11 months vs every 38 months) and iOS requirement (11.0 vs 15.0). On ads, in-app purchases and device support there is nothing between them.

DIAX costs $19.99 and Skeleton Study Guide $6.99 up front. Neither carries in-app purchases, so what you see is what you pay.

DIAX ships an update every 11 months, Skeleton Study Guide every 38 months. The most recent releases landed on October 16, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | DIAX | Skeleton Study Guide |
| --- | --- | --- |
| Price | $19.99 | **$6.99** |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/diax-bone-age/id1296654435/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 11 months** | Every 38 months |
| Monetization | Paid | — |
| Best chart rank | — | **#195** |
| Size | 45 MB | 16 MB |
| Requires iOS | **11.0** | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 17+ | 4+ |
| Developer | [SANTOS DIAS MEDICAL CARE SS](https://appshunter.io/developer/1296654434) | [Ryan Bittorf](https://appshunter.io/developer/650449038) |

## What reviewers say

### DIAX

[App page](https://appshunter.io/ios/app/diax-bone-age/id1296654435)

This medical app simplifies understanding wrist X-rays for bone age assessment. It uses simplified drawings and daily radiographs to help students and physicians quickly determine bone age based on gender and age group.

**Highlights:** Wrist X-ray analysis, Bone age assessment, Simplified drawings, Daily radiograph images, Gender and age group specific

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

**In-app purchases:** none


### Skeleton Study Guide

[App page](https://appshunter.io/ios/app/skeleton-study-guide/id6446384636)

**Currently charting:** #195 Top Paid · Medical (US App Store)

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

**In-app purchases:** none


## Frequently asked questions

### Is DIAX free?

DIAX costs $19.99, with no in-app purchases.

### Is Skeleton Study Guide free?

Skeleton Study Guide costs $6.99, with no in-app purchases.

### Do DIAX or Skeleton Study Guide have ads?

Neither DIAX nor Skeleton Study Guide shows ads.

### Which is updated more often, DIAX or Skeleton Study Guide?

DIAX ships an update every 11 months, and Skeleton Study Guide every 38 months. Most recently, DIAX was updated on October 16, 2026 and Skeleton Study Guide on October 6, 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.*