# Wheels Speed Calculator vs OBD JScan

The clearest difference is review sentiment: OBD JScan at 80% against Wheels Speed Calculator's 0%. OBD JScan also leads on rating (4.7 vs 1.0) and ads (none vs shown). Wheels Speed Calculator's advantage is in-app purchases (none vs 7). On price, device support and iOS requirement there is nothing between them.

Both are free to download. OBD JScan sells 6 one-off in-app purchases. Wheels Speed Calculator asks for nothing beyond the download.

OBD JScan holds the better App Store score, 4.7 against 1.0. That said, the two scores are not equally well evidenced: OBD JScan has 1.3K ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 0% of Wheels Speed Calculator's written reviews are positive against 80% of OBD JScan's.

Wheels Speed Calculator ships an update every 6 months, OBD JScan every 3 weeks. The most recent releases landed on October 8, 2026 and October 29, 2026 respectively.

## The numbers

| Metric | Wheels Speed Calculator | OBD JScan |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [1.0 (1 ratings)](https://appshunter.io/ios/app/wheels-speed-calculator/id578189352/reviews) | **[4.7 (1.3K ratings)](https://appshunter.io/ios/app/obd-jscan/id1445903514/reviews)** |
| Number of ratings | 1 | **1.3K** |
| Positive reviews | 0.0% of reviews | **79.6% of reviews** |
| In-app purchases | **No** | Yes |
| Ads | Yes | **No** |
| Update frequency | Every 6 months | **Every 3 weeks** |
| Monetization | **Ad-supported** | Free with in-app purchases |
| Size | 44 MB | 403 MB |
| Requires iOS | **12.0** | 13.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod** |
| Age rating | 4+ | 12+ |
| Developer | [Liutauras Stravinskas](https://appshunter.io/developer/578189355) | [Piotr Bialic](https://appshunter.io/developer/960266498) |

## What reviewers say

### Wheels Speed Calculator

[App page](https://appshunter.io/ios/app/wheels-speed-calculator/id578189352)

Calculate the error in your speedometer when using tires of different dimensions than recommended by the manufacturer. It helps you find tire sizes that minimize speedometer inaccuracies for your vehicle.

**Highlights:** Calculate speedometer error, Check speed differences with different tire sizes, Select tire sizes from R4/80/25 to R26/460/100, Find tire sizes for minimum speedometer error, Suggests 100 tire sizes for smallest error

**Features:** Vision Pro support

**In-app purchases:** none


### OBD JScan

[App page](https://appshunter.io/ios/app/obd-jscan/id1445903514)

This diagnostic application provides in-depth access to vehicle modules, allowing users to read and clear trouble codes, view live sensor data, and access vehicle settings. It supports a wide range of Jeep, Chrysler, and Dodge models, offering powerful customization and diagnostic features.

**Highlights:** Read and clear diagnostic trouble codes, Access live data from all vehicle sensors, View vehicle settings and module information, Supports ABS, transmission, and other modules, Wide compatibility with Jeep, Chrysler, Dodge, Enables features locked by dealers

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

**In-app purchases (6)**

| Purchase | Price | Billing |
| --- | --- | --- |
| + 1 garage license | $9.99 | one-time |
| 1 VIN license | $20.99 | one-time |
| Add 1 VIN Vehicle Slot | $20.99 | one-time |
| 3 VIN licenses | $54.99 | one-time |
| 5 VIN Licenses | $84.99 | one-time |
| 10 VIN Licenses | $149.99 | one-time |

**What reviewers like**

- 🚀 Easy to use
- 🔧 Powerful customization options
- 👍 Excellent customer support
- 💡 Useful diagnostic and monitoring features
- 🔓 Enables features otherwise locked by dealer

**What reviewers complain about**

- 🐛 Occasional connectivity issues
- 🔌 Requires additional hardware purchase
- ⚠️ Compatibility issues with newer vehicle models
- 🕰️ Slow performance in certain scenarios

**Reported bugs**

- Inability to save/export diagnostic data
- Inconsistent behavior when changing vehicle settings

**Requested features**

- Expanded vehicle compatibility
- Improved stability and reliability
- Enhanced user interface and guidance
- Integration with other vehicle apps/services


## Frequently asked questions

### Is Wheels Speed Calculator free?

Wheels Speed Calculator is free to download, with no in-app purchases.

### Is OBD JScan free?

OBD JScan is free to download, with in-app purchases available.

### Which has better reviews, Wheels Speed Calculator or OBD JScan?

OBD JScan is rated higher. Wheels Speed Calculator averages 1.0 out of 5 from 1 ratings, while OBD JScan averages 4.7 from 1.3K ratings.

### Do Wheels Speed Calculator or OBD JScan have ads?

Wheels Speed Calculator shows ads; OBD JScan does not.

### Which is updated more often, Wheels Speed Calculator or OBD JScan?

Wheels Speed Calculator ships an update every 6 months, and OBD JScan every 3 weeks. Most recently, Wheels Speed Calculator was updated on October 8, 2026 and OBD JScan on October 29, 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.*