# Retinal vs Horizontal Accelerometer

The clearest difference is ads: Retinal at none against Horizontal Accelerometer's shown. Retinal also leads on update cadence (fortnightly vs every 6 weeks). Horizontal Accelerometer's advantage is device support (3 vs 1) and iOS requirement (13.0 vs 17.0). On price and in-app purchases there is nothing between them.

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

Retinal ships an update fortnightly, Horizontal Accelerometer every 6 weeks. The most recent releases landed on September 8, 2026 and September 12, 2026 respectively.

## The numbers

| Metric | Retinal | Horizontal Accelerometer |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 50.0% of reviews |
| In-app purchases | No | No |
| Ads | **No** | Yes |
| Update frequency | **Fortnightly** | Every 6 weeks |
| Monetization | — | Ad-supported |
| Size | 1 MB | 6 MB |
| Requires iOS | 17.0 | **13.0** |
| Devices | iPhone | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Nico Rohrbach](https://appshunter.io/developer/662717596) | [Takao Ichimura](https://appshunter.io/developer/1474061593) |

## What reviewers say

### Retinal

[App page](https://appshunter.io/ios/app/retinal/id1564557619)

**Features:** macOS Compatibility

**In-app purchases:** none


### Horizontal Accelerometer

[App page](https://appshunter.io/ios/app/horizontal-accelerometer/id6444095874)

This tool measures real-time horizontal acceleration, deceleration, and lateral G-force for automobiles. It features color-coded zones and sounds for easy understanding while driving and can also be used for engineering education and evaluating structural rigidity.

**Highlights:** Real-time horizontal acceleration measurement, Measures deceleration and lateral G-force, Color zones and sound alerts for values, Calibration for accurate readings, Peak hold and max value tracking, Adjustable color zone thresholds and sound

**Features:** Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Retinal free?

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

### Is Horizontal Accelerometer free?

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

### Do Retinal or Horizontal Accelerometer have ads?

Horizontal Accelerometer shows ads; Retinal does not.

### Which is updated more often, Retinal or Horizontal Accelerometer?

Retinal ships an update fortnightly, and Horizontal Accelerometer every 6 weeks. Most recently, Retinal was updated on September 8, 2026 and Horizontal Accelerometer on September 12, 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.*