# CDL Prep vs OD

The clearest difference is in-app purchases: OD at none against CDL Prep's 2. OD also leads on ads (none vs shown) and rating (5.0 vs 4.8). CDL Prep's advantage is ratings volume (2.6K vs 4). On price, update cadence and device support there is nothing between them.

Both are free to download. CDL Prep sells 2 in-app purchases, starting at $6.99 per 7 days. OD asks for nothing beyond the download.

OD holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: CDL Prep has 2.6K ratings behind it against 4, so its average is the more settled of the two.

CDL Prep ships an update every 8 months, OD every 4 months. The most recent releases landed on October 15, 2026 and October 9, 2026 respectively.

## The numbers

| Metric | CDL Prep | OD |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.8 (2.6K ratings)](https://appshunter.io/ios/app/cdl-prep-exams-and-study-guide/id1455037780/reviews) | **[5.0 (4 ratings)](https://appshunter.io/ios/app/od-me/id1496024129/reviews)** |
| Number of ratings | **2.6K** | 4 |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | Yes | **No** |
| Update frequency | Every 8 months | **Every 4 months** |
| Monetization | Free with in-app purchases | **Free** |
| Size | 56 MB | 40 MB |
| Requires iOS | 15.1 | **12.4** |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 17+ |
| Developer | [LineCentury](https://appshunter.io/developer/1057772456) | [University of Maine System](https://appshunter.io/developer/1453562095) |

## What reviewers say

### CDL Prep

[App page](https://appshunter.io/ios/app/cdl-prep-exams-and-study-guide/id1455037780)

Prepare for your Commercial Driver's License (CDL) exam with comprehensive study materials and practice tests. This app offers real test questions covering general knowledge, hazmat, passenger vehicles, and air brakes, with detailed answers to help you pass.

**Highlights:** Free CDL preparation, Real test questions, Practice general knowledge tests, All CDL test answers, Covers hazmat and air brakes

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Subscription 1 Week | $6.99 | per 7 days |
| Unlock Everything | $15.99 | one-time |


### OD

[App page](https://appshunter.io/ios/app/od-me/id1496024129)

Learn how to administer naloxone for overdose rescue. This educational tool provides instructions for nasal and intramuscular naloxone, signs of overdose, and where to obtain the medication. It also covers opioid types and what to do while waiting for medical help.

**Highlights:** Naloxone administration instructions (nasal and intramuscular), Signs of overdose identification, Naloxone acquisition and storage guidance, Information on opioid types, Steps while waiting for paramedics, Text, diagrams, and voice-overs

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is CDL Prep free?

CDL Prep is free to download, with in-app purchases available.

### Is OD free?

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

### Which has better reviews, CDL Prep or OD?

OD is rated higher. CDL Prep averages 4.8 out of 5 from 2.6K ratings, while OD averages 5.0 from 4 ratings.

### Do CDL Prep or OD have ads?

CDL Prep shows ads; OD does not.

### Which is updated more often, CDL Prep or OD?

CDL Prep ships an update every 8 months, and OD every 4 months. Most recently, CDL Prep was updated on October 15, 2026 and OD 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.*