# Birdathon vs Circle & Sphere

The clearest difference is rating: Birdathon at 4.7 against Circle & Sphere's 4.0. Birdathon also leads on monetization model (free vs free with in-app purchases) and ratings volume (15 vs 4). Circle & Sphere's advantage is update cadence (every 3 weeks vs every 4 months). On price, review sentiment, ads and in-app purchases there is nothing between them.

Both are free to download. Birdathon sells 4 one-off in-app purchases and Circle & Sphere sells 8 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

Birdathon holds the better App Store score, 4.7 against 4.0. Both are backed by a comparable volume of ratings — 15 and 4 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

Birdathon ships an update every 4 months, Circle & Sphere every 3 weeks. Both last shipped on September 19, 2026.

## The numbers

| Metric | Birdathon | Circle & Sphere |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (15 ratings)](https://appshunter.io/ios/app/birdathon/id1211977440/reviews)** | [4.0 (4 ratings)](https://appshunter.io/ios/app/circle-and-sphere/id1564077078/reviews) |
| Number of ratings | **15** | 4 |
| Positive reviews | 100.0% of reviews | 100.0% of reviews |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 4 months | **Every 3 weeks** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 192 MB | 180 MB |
| Requires iOS | 16.1 | **15.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Barry Langdon-Lassagne](https://appshunter.io/developer/730758814) | [Glindemann, Sennoun, Langer GbR](https://appshunter.io/developer/1024972809) |

## 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 |


### Circle & Sphere

[App page](https://appshunter.io/ios/app/circle-and-sphere/id1564077078)

Instantly solve geometry problems for homework and exams. Calculate circle and sphere properties with step-by-step solutions. Access learning videos and manage your calculations.

**Highlights:** Circle calculations (radius, diameter, circumference, area), Sphere calculations (surface area, volume), Circular sector calculations, Step-by-step solutions, Learning videos, Solution management

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

**In-app purchases (8)**

| Purchase | Price | Billing |
| --- | --- | --- |
| +30 User Tokens | $0.29 | one-time |
| +1 Convenience Token / 6h, max. +2 | $0.59 | one-time |
| +2 Convenience Tokens / 6h, max. +4 | $0.99 | one-time |
| +150 User Tokens | $0.99 | one-time |
| +300 User Tokens | $1.49 | one-time |
| +4 Convenience Tokens / 6h, max. +8 | $1.59 | one-time |
| Remove Ads | $2.99 | one-time |
| Lifetime Access | $2.99 | one-time |


## Frequently asked questions

### Is Birdathon free?

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

### Is Circle & Sphere free?

Circle & Sphere is free to download, with in-app purchases available.

### Which has better reviews, Birdathon or Circle & Sphere?

Birdathon is rated higher. Birdathon averages 4.7 out of 5 from 15 ratings, while Circle & Sphere averages 4.0 from 4 ratings.

### Do Birdathon or Circle & Sphere have ads?

Neither Birdathon nor Circle & Sphere shows ads.

### Which is updated more often, Birdathon or Circle & Sphere?

Birdathon ships an update every 4 months, and Circle & Sphere every 3 weeks. Most recently, Birdathon was updated on September 19, 2026 and Circle & Sphere on September 19, 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.*