# RIAT vs Doppler Effect Calculator

The clearest difference is price: RIAT at Free against Doppler Effect Calculator's $2.99. RIAT also leads on iOS requirement (10.3 vs 17.6). On rating, ratings volume, update cadence and ads there is nothing between them.

RIAT is free to download; Doppler Effect Calculator costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.

On the App Store both sit at effectively the same score — 5.0 for RIAT against 5.0 for Doppler Effect Calculator. Both are backed by a comparable volume of ratings — 2 and 1 respectively.

RIAT ships an update every 34 months, Doppler Effect Calculator every 26 months. The most recent releases landed on October 19, 2026 and October 8, 2026 respectively.

## The numbers

| Metric | RIAT | Doppler Effect Calculator |
| --- | --- | --- |
| Price | **Free** | $2.99 |
| Rating | [5.0 (2 ratings)](https://appshunter.io/ios/app/riat/id1136335542/reviews) | [5.0 (1 ratings)](https://appshunter.io/ios/app/doppler-effect-calculator/id1410084954/reviews) |
| Number of ratings | **2** | 1 |
| Positive reviews | — | 0.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 34 months | **Every 26 months** |
| Monetization | **Free** | Paid |
| Size | 45 MB | 1 MB |
| Requires iOS | **10.3** | 17.6 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [County of Palm Beach](https://appshunter.io/developer/1520530049) | [Nitrio](https://appshunter.io/developer/321121189) |

## What reviewers say

### RIAT

[App page](https://appshunter.io/ios/app/riat/id1136335542)

This tool enables first responders and local government officials to quickly report disaster damage. It provides disaster managers with an immediate countywide overview within hours of an event.

**Highlights:** Submit damage reports, Immediate countywide overview, Post-disaster assessment, For first responders, For local government employees

**In-app purchases:** none


### Doppler Effect Calculator

[App page](https://appshunter.io/ios/app/doppler-effect-calculator/id1410084954)

This physics and math calculator helps determine the frequency of sound waves when the source or observer is in motion. It provides instant calculations with copyable results and includes reference formulas. The app supports various units and high precision, working seamlessly on iOS devices.

**Highlights:** Instant calculations, Copyable results, Reference formulas included, Supports 16 decimal places, Multiple unit support, Ad-free and private

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

**In-app purchases:** none


## Frequently asked questions

### Is RIAT free?

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

### Is Doppler Effect Calculator free?

Doppler Effect Calculator costs $2.99, with no in-app purchases.

### Which has better reviews, RIAT or Doppler Effect Calculator?

RIAT and Doppler Effect Calculator are both rated 5.0 out of 5 on the App Store, from 2 and 1 ratings respectively.

### Do RIAT or Doppler Effect Calculator have ads?

Neither RIAT nor Doppler Effect Calculator shows ads.

### Which is updated more often, RIAT or Doppler Effect Calculator?

RIAT ships an update every 34 months, and Doppler Effect Calculator every 26 months. Most recently, RIAT was updated on October 19, 2026 and Doppler Effect Calculator on October 8, 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.*