# CosmoCalc vs Celestia

The clearest difference is rating: CosmoCalc at 5.0 against Celestia's 4.4. CosmoCalc also leads on in-app purchases (none vs 4) and review sentiment (100% vs 79%). Celestia's advantage is update cadence (every 2 weeks vs every 6 months) and ratings volume (331 vs 4). On price and ads there is nothing between them.

Both are free to download. Celestia sells 4 in-app purchases, starting at $0.99 per 7 days. CosmoCalc asks for nothing beyond the download.

CosmoCalc holds the better App Store score, 5.0 against 4.4. That said, the two scores are not equally well evidenced: Celestia has 331 ratings behind it against 4, so its average is the more settled of the two. Written reviews point the same way: 100% of CosmoCalc's written reviews are positive against 79% of Celestia's.

CosmoCalc ships an update every 6 months, Celestia every 2 weeks. The most recent releases landed on October 6, 2026 and October 15, 2026 respectively.

## The numbers

| Metric | CosmoCalc | Celestia |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[5.0 (4 ratings)](https://appshunter.io/ios/app/cosmocalc/id334569654/reviews)** | [4.4 (331 ratings)](https://appshunter.io/ios/app/celestia-space-simulator/id1500434829/reviews) |
| Number of ratings | 4 | **331** |
| Positive reviews | **100.0% of reviews** | 79.3% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 6 months | **Every 2 weeks** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 1 MB | 545 MB |
| Requires iOS | **9.0** | 15.0 |
| Devices | iPhone, iPod | **iPhone, iPad, iPod, Mac** |
| Age rating | 4+ | 4+ |
| Developer | [Eli Rykoff](https://appshunter.io/developer/318275933) | [林峰 李](https://appshunter.io/developer/1186547508) |

## What reviewers say

### CosmoCalc

[App page](https://appshunter.io/ios/app/cosmocalc/id334569654)

This app calculates astronomical distances and scales based on user-selected cosmological parameters. It offers a simple interface for astronomers, students, and enthusiasts to quickly determine various cosmic measurements.

**Highlights:** Select cosmological parameters (H0, Ωm, ΩΛ), Choose from common reference cosmologies, Calculate luminosity distance, Determine angular diameter distance, Calculate lookback time, Find age of the Universe, Compute comoving volume and critical density

**Features:** macOS Compatibility

**In-app purchases:** none


### Celestia

[App page](https://appshunter.io/ios/app/celestia-space-simulator/id1500434829)

Explore the universe in real-time 3D. Visit planets, moons, star clusters, and galaxies, viewing them from any point in space and time. Customize your experience with expandable content and detailed simulations.

**Highlights:** Real-time 3D space visualization, Explore planets, moons, stars, galaxies, Accurate solar system object positions, Interactive planetarium mode, Expandable content with add-ons, Customizable celestial databases

**Features:** Game Controller support, Vision Pro support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Celestia PLUS (Weekly) | $0.99 | per 7 days |
| Celestia PLUS (Monthly) | $1.99 | per month |
| Celestia PLUS (Yearly) | $19.99 | per year |
| Celestia PLUS (Lifetime) | $79.99 | one-time |

**What reviewers like**

- ⭐ Realistic space simulation
- 🌌 Ability to explore galaxies and star systems
- 🔍 Detailed planet and moon textures
- 📷 Great for taking screenshots
- 🤖 Reminds users of Space Engine

**What reviewers complain about**

- 🐛 Occasional crashes and glitches
- 🌌 Limited exploration beyond Milky Way and Andromeda
- 🌍 Flat terrain on planets
- 🔍 Lack of detail on some celestial objects
- 🔒 Paywall for some features

**Reported bugs**

- Milky Way and other galaxy textures not loading properly
- Crashes when using certain add-ons
- Issues with planet and moon orbits not being accurate

**Requested features**

- Add more exoplanets and distant star systems
- Implement terrain generation for planets
- Expand to include more galaxies and the overall universe structure
- Add support for black holes, pulsars, and other exotic objects
- Improve controls and camera movement


## Frequently asked questions

### Is CosmoCalc free?

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

### Is Celestia free?

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

### Which has better reviews, CosmoCalc or Celestia?

CosmoCalc is rated higher. CosmoCalc averages 5.0 out of 5 from 4 ratings, while Celestia averages 4.4 from 331 ratings.

### Do CosmoCalc or Celestia have ads?

Neither CosmoCalc nor Celestia shows ads.

### Which is updated more often, CosmoCalc or Celestia?

CosmoCalc ships an update every 6 months, and Celestia every 2 weeks. Most recently, CosmoCalc was updated on October 6, 2026 and Celestia on October 15, 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.*