# FDR Calculator vs FireSignal

The clearest difference is in-app purchases: FireSignal at none against FDR Calculator's 1. FireSignal also leads on update cadence (every 3 days vs every 4 months). FDR Calculator's advantage is ads (none vs shown). On price, device support and iOS requirement there is nothing between them.

Both are free to download. FDR Calculator sells 1 in-app purchase, starting at $1.99 per month. FireSignal asks for nothing beyond the download.

FDR Calculator ships an update every 4 months, FireSignal every 3 days. The most recent releases landed on November 6, 2026 and October 31, 2026 respectively.

## The numbers

| Metric | FDR Calculator | FireSignal |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | Every 4 months | **Every 3 days** |
| Monetization | Free with in-app purchases | — |
| Size | 35 MB | 7 MB |
| Requires iOS | 15.0 | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Alan Richert](https://appshunter.io/developer/527055673) | [Rutger Harder](https://appshunter.io/developer/6808944670) |

## What reviewers say

### FDR Calculator

[App page](https://appshunter.io/ios/app/fdr-calculator/id527055670)

Instantly calculate fire danger ratings with professional-grade algorithms. Offers real-time weather data integration, visual danger level displays, and detailed action recommendations for informed fire prevention and management.

**Highlights:** Instant Fire Danger Index calculations, Real-time weather data integration, Visual color-coded danger levels, Detailed action recommendations, Manual calculator for offline use, Automatic location detection

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Weather Pro (Monthly) | $1.99 | per month |


### FireSignal

[App page](https://appshunter.io/ios/app/firesignal-wildfires/id6808944668)

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

**In-app purchases:** none


## Frequently asked questions

### Is FDR Calculator free?

FDR Calculator is free to download, with in-app purchases available.

### Is FireSignal free?

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

### Do FDR Calculator or FireSignal have ads?

FireSignal shows ads; FDR Calculator does not.

### Which is updated more often, FDR Calculator or FireSignal?

FDR Calculator ships an update every 4 months, and FireSignal every 3 days. Most recently, FDR Calculator was updated on November 6, 2026 and FireSignal on October 31, 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.*