# Hydrology Formulator vs FieldX Sampling

The clearest difference is review sentiment: FieldX Sampling at 100% against Hydrology Formulator's 0%. FieldX Sampling also leads on in-app purchases (none vs 1) and update cadence (every 10 days vs every 6 months). Hydrology Formulator's advantage is rating (5.0 vs 4.0). On price, ads, monetization model and device support there is nothing between them.

Both are free to download. Hydrology Formulator sells 1 one-off in-app purchase. FieldX Sampling asks for nothing beyond the download.

Hydrology Formulator holds the better App Store score, 5.0 against 4.0. That said, the two scores are not equally well evidenced: FieldX Sampling has 5 ratings behind it against 1, so its average is the more settled of the two. Written reviews complicate that: 0% of Hydrology Formulator's written reviews are positive against 100% of FieldX Sampling's, so the app with the better star average is not the one people write more warmly about.

Hydrology Formulator ships an update every 6 months, FieldX Sampling every 10 days. The most recent releases landed on October 8, 2026 and October 21, 2026 respectively.

## The numbers

| Metric | Hydrology Formulator | FieldX Sampling |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/hydrology-formulator/id346512904/reviews)** | [4.0 (5 ratings)](https://appshunter.io/ios/app/fieldx-sampling/id930155256/reviews) |
| Number of ratings | 1 | **5** |
| Positive reviews | 0.0% of reviews | **100.0% of reviews** |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 6 months | **Every 10 days** |
| Monetization | Free | Free |
| Size | 18 MB | 6 MB |
| Requires iOS | 18.6 | **15.6** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Historycentral.com](https://appshunter.io/developer/1744330560) | [FieldX Inc.](https://appshunter.io/developer/1480558229) |

## What reviewers say

### Hydrology Formulator

[App page](https://appshunter.io/ios/app/hydrology-formulator/id346512904)

This app provides a comprehensive collection of over 1,000 formulas, calculators, and conversions for hydrology and civil engineering. It covers a wide range of topics including groundwater, stormwater, pipe flow, and water pollution.

**Highlights:** 1,000+ formulas and calculators, Groundwater analysis tools, Stormwater design calculations, Open channel and pipe flow equations, Water pollution modeling, Conversions and reference data

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Version | $3.99 | one-time |


### FieldX Sampling

[App page](https://appshunter.io/ios/app/fieldx-sampling/id930155256)

This app helps agricultural professionals collect soil samples in the field. It allows users to create and manage sampling points, navigate to locations, and log journal entries. The app supports offline use and integrates with desktop software for data management.

**Highlights:** Create and update sampling journal entries, Add, move, and delete sampling points, Navigate to sampling points with direction and distance, Mark sampling points as completed, Add new sampling points at GPS location, Work online or offline, Import/Export points from FieldX Office

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

**In-app purchases:** none


## Frequently asked questions

### Is Hydrology Formulator free?

Hydrology Formulator is free to download, with in-app purchases available.

### Is FieldX Sampling free?

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

### Which has better reviews, Hydrology Formulator or FieldX Sampling?

Hydrology Formulator is rated higher. Hydrology Formulator averages 5.0 out of 5 from 1 ratings, while FieldX Sampling averages 4.0 from 5 ratings.

### Do Hydrology Formulator or FieldX Sampling have ads?

Neither Hydrology Formulator nor FieldX Sampling shows ads.

### Which is updated more often, Hydrology Formulator or FieldX Sampling?

Hydrology Formulator ships an update every 6 months, and FieldX Sampling every 10 days. Most recently, Hydrology Formulator was updated on October 8, 2026 and FieldX Sampling on October 21, 2026.

---

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