# Acid Base pH vs Birdathon

The clearest difference is price: Birdathon at Free against Acid Base pH's $3.99. Birdathon also leads on ratings volume (15 vs 1). Acid Base pH's advantage is in-app purchases (none vs 4) and rating (5.0 vs 4.7). On review sentiment, update cadence, ads and device support there is nothing between them.

Birdathon is free to download; Acid Base pH costs $3.99 up front. Birdathon sells 4 one-off in-app purchases. Acid Base pH asks for nothing beyond the download.

Acid Base pH holds the better App Store score, 5.0 against 4.7. That said, the two scores are not equally well evidenced: Birdathon has 15 ratings behind it against 1, so its average is the more settled of the two. Written reviews split almost evenly too, at 100% and 100% positive.

Acid Base pH ships an update every 3 months, Birdathon every 4 months. The most recent releases landed on August 20, 2026 and September 19, 2026 respectively.

## The numbers

| Metric | Acid Base pH | Birdathon |
| --- | --- | --- |
| Price | $3.99 | **Free** |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/acid-base-ph/id977951851/reviews)** | [4.7 (15 ratings)](https://appshunter.io/ios/app/birdathon/id1211977440/reviews) |
| Number of ratings | 1 | **15** |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | **Every 3 months** | Every 4 months |
| Monetization | Paid | **Free** |
| Size | 2 MB | 192 MB |
| Requires iOS | 17.1 | **16.1** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Roman Volinsky](https://appshunter.io/developer/977951850) | [Barry Langdon-Lassagne](https://appshunter.io/developer/730758814) |

## What reviewers say

### Acid Base pH

[App page](https://appshunter.io/ios/app/acid-base-ph/id977951851)

Accurately estimate pH values for acid-base aqueous systems. Calculate pH for weak and strong acids/bases, plot titration curves, and find equivalent points. Export data and find titrant volumes for desired pH.

**Highlights:** Estimate pH of acid-base solutions, Plot titration curves, Find pH and titrant volume at equivalent points, Export titration plots as image or data, Calculate titrant volume for desired pH, Includes list of common indicators

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

**In-app purchases:** none


### Birdathon

[App page](https://appshunter.io/ios/app/birdathon/id1211977440)

This app helps birdwatchers create and organize detailed checklists of their observations. It automatically records time and location, allowing for easy editing and customization. Users can visualize their sightings on maps, add field notes, and export data for sharing or further analysis.

**Highlights:** Observation-centric checklists, Automatic time and location recording, Customizable maps with boundary overlays, Field notes for additional observations, Multiple checklist sorting options, Data export to CSV and other formats, Create checklist templates

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Good Tip | $0.99 | one-time |
| Great Tip | $1.99 | one-time |
| Amazing Tip | $2.99 | one-time |
| Incredible Tip | $4.99 | one-time |


## Frequently asked questions

### Is Acid Base pH free?

Acid Base pH costs $3.99, with no in-app purchases.

### Is Birdathon free?

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

### Which has better reviews, Acid Base pH or Birdathon?

Acid Base pH is rated higher. Acid Base pH averages 5.0 out of 5 from 1 ratings, while Birdathon averages 4.7 from 15 ratings.

### Do Acid Base pH or Birdathon have ads?

Neither Acid Base pH nor Birdathon shows ads.

### Which is updated more often, Acid Base pH or Birdathon?

Acid Base pH ships an update every 3 months, and Birdathon every 4 months. Most recently, Acid Base pH was updated on August 20, 2026 and Birdathon on September 19, 2026.

---

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