# Horizontal Accelerometer vs Reaction Time Test

The clearest difference is ads: Reaction Time Test at none against Horizontal Accelerometer's shown. Reaction Time Test also leads on update cadence (every 8 days vs every 6 weeks). Horizontal Accelerometer's advantage is iOS requirement (13.0 vs 17.0). On price, in-app purchases and device support there is nothing between them.

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

Horizontal Accelerometer ships an update every 6 weeks, Reaction Time Test every 8 days. The most recent releases landed on October 7, 2026 and October 4, 2026 respectively.

## The numbers

| Metric | Horizontal Accelerometer | Reaction Time Test |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 50.0% of reviews | — |
| In-app purchases | No | No |
| Ads | Yes | **No** |
| Update frequency | Every 6 weeks | **Every 8 days** |
| Monetization | Ad-supported | — |
| Size | 6 MB | 5 MB |
| Requires iOS | **13.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Takao Ichimura](https://appshunter.io/developer/1474061593) | [Jinwan Kim](https://appshunter.io/developer/1446513824) |

## What reviewers say

### 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


### Reaction Time Test

[App page](https://appshunter.io/ios/app/reaction-time-test-millis/id6805464656)

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

**In-app purchases:** none


## Frequently asked questions

### Is Horizontal Accelerometer free?

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

### Is Reaction Time Test free?

Reaction Time Test is free to download, with no in-app purchases.

### Do Horizontal Accelerometer or Reaction Time Test have ads?

Horizontal Accelerometer shows ads; Reaction Time Test does not.

### Which is updated more often, Horizontal Accelerometer or Reaction Time Test?

Horizontal Accelerometer ships an update every 6 weeks, and Reaction Time Test every 8 days. Most recently, Horizontal Accelerometer was updated on October 7, 2026 and Reaction Time Test on October 4, 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.*