# Fertilizer Calc App vs SOS Viewer

The clearest difference is in-app purchases: SOS Viewer at none against Fertilizer Calc App's 2. SOS Viewer also leads on update cadence (fortnightly vs every 2 months). On price, ads, device support and iOS requirement there is nothing between them.

Both are free to download. Fertilizer Calc App sells 2 in-app purchases, starting at $1.99 per month. SOS Viewer asks for nothing beyond the download.

Fertilizer Calc App ships an update every 2 months, SOS Viewer fortnightly. The most recent releases landed on October 18, 2026 and October 15, 2026 respectively.

## The numbers

| Metric | Fertilizer Calc App | SOS Viewer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[1.0 (1 ratings)](https://appshunter.io/ios/app/fertilizer-calc-app/id1450299266/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 2 months | **Fortnightly** |
| Monetization | Free with in-app purchases | — |
| Size | 18 MB | 66 MB |
| Requires iOS | 16.0 | **15.6** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Alberto Giambone](https://appshunter.io/developer/1412648174) | [Tech Tree Sdn Bhd](https://appshunter.io/developer/1756843252) |

## What reviewers say

### Fertilizer Calc App

[App page](https://appshunter.io/ios/app/fertilizer-calc-app/id1450299266)

This app helps farmers precisely calculate fertilization needs for their crops. Users can input field details, set fertilization targets for key nutrients like N, P, and K, and determine the required application rates per hectare. It also supports custom area units for flexible calculations.

**Highlights:** Calculate N, P, K, MG, CA needs per field, Set fertilization targets, Determine Kg/Ha for each element, Add custom area units, Supports multiple custom units with Pro membership

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Custom Area Unit | $1.99 | per month |
| Custom Area Unit | $9.99 | per year |


### SOS Viewer

[App page](https://appshunter.io/ios/app/sos-viewer/id6742965163)

**In-app purchases:** none


## Frequently asked questions

### Is Fertilizer Calc App free?

Fertilizer Calc App is free to download, with in-app purchases available.

### Is SOS Viewer free?

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

### Do Fertilizer Calc App or SOS Viewer have ads?

Neither Fertilizer Calc App nor SOS Viewer shows ads.

### Which is updated more often, Fertilizer Calc App or SOS Viewer?

Fertilizer Calc App ships an update every 2 months, and SOS Viewer fortnightly. Most recently, Fertilizer Calc App was updated on October 18, 2026 and SOS Viewer on October 15, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*