# Birdathon vs Formula & Units

The clearest difference is price: Birdathon at Free against Formula & Units's $3.99. Formula & Units's advantage is in-app purchases (none vs 4) and update cadence (every 2 months vs every 4 months). On ads, device support and iOS requirement there is nothing between them.

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

Birdathon ships an update every 4 months, Formula & Units every 2 months. The most recent releases landed on October 24, 2026 and August 20, 2026 respectively.

## The numbers

| Metric | Birdathon | Formula & Units |
| --- | --- | --- |
| Price | **Free** | $3.99 |
| Rating | **[4.7 (15 ratings)](https://appshunter.io/ios/app/birdathon/id1211977440/reviews)** | — |
| Number of ratings | **15** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 2 months** |
| Monetization | Free | — |
| Size | 192 MB | 1 MB |
| Requires iOS | 16.1 | **16.0** |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Barry Langdon-Lassagne](https://appshunter.io/developer/730758814) | [Roman Volinsky](https://appshunter.io/developer/977951850) |

## What reviewers say

### 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 |


### Formula & Units

[App page](https://appshunter.io/ios/app/formula-and-units/id1255813016)

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

**In-app purchases:** none


## Frequently asked questions

### Is Birdathon free?

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

### Is Formula & Units free?

Formula & Units costs $3.99, with no in-app purchases.

### Do Birdathon or Formula & Units have ads?

Neither Birdathon nor Formula & Units shows ads.

### Which is updated more often, Birdathon or Formula & Units?

Birdathon ships an update every 4 months, and Formula & Units every 2 months. Most recently, Birdathon was updated on October 24, 2026 and Formula & Units on August 20, 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.*