# Planetary Clock vs Universe Size Comparison

The clearest difference is rating: Planetary Clock at 4.9 against Universe Size Comparison's 3.1. Planetary Clock also leads on price ($0.99 vs $1.99) and iOS requirement (11.4 vs 13.0). Universe Size Comparison's advantage is update cadence (every 4 months vs every 27 months) and review sentiment (67% vs 57%). On ratings volume, ads, in-app purchases and monetization model there is nothing between them.

Planetary Clock costs $0.99 and Universe Size Comparison $1.99 up front. Neither carries in-app purchases, so what you see is what you pay.

Planetary Clock holds the better App Store score, 4.9 against 3.1. Both are backed by a comparable volume of ratings — 34 and 29 respectively. Written reviews complicate that: 57% of Planetary Clock's written reviews are positive against 67% of Universe Size Comparison's, so the app with the better star average is not the one people write more warmly about.

Planetary Clock ships an update every 27 months, Universe Size Comparison every 4 months. The most recent releases landed on September 30, 2026 and September 15, 2026 respectively.

## The numbers

| Metric | Planetary Clock | Universe Size Comparison |
| --- | --- | --- |
| Price | **$0.99** | $1.99 |
| Rating | **[4.9 (34 ratings)](https://appshunter.io/ios/app/planetary-clock/id812876503/reviews)** | [3.1 (29 ratings)](https://appshunter.io/ios/app/universe-size-comparison/id1473946290/reviews) |
| Number of ratings | **34** | 29 |
| Positive reviews | 57.1% of reviews | **66.7% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 27 months | **Every 4 months** |
| Monetization | Paid | Paid |
| Size | 14 MB | 411 MB |
| Requires iOS | **11.4** | 13.0 |
| Devices | iPhone, iPad, iPod | **iPhone, iPad, iPod, Apple TV** |
| Age rating | 4+ | 4+ |
| Developer | [Piotr Knapczyk](https://appshunter.io/developer/1541886746) | [Daniele Citi](https://appshunter.io/developer/1187632258) |

## What reviewers say

### Planetary Clock

[App page](https://appshunter.io/ios/app/planetary-clock/id812876503)

Visualize the precise positions of all planets in the Solar System for any given day. It uses accurate NASA data for orbital calculations and relative planet sizing, offering a clear, educational view of celestial mechanics.

**Highlights:** Real-time planet positions, Accurate orbital calculations, Uses NASA data, Relative planet sizing, Educational solar system view

**Features:** macOS Compatibility

**In-app purchases:** none


### Universe Size Comparison

[App page](https://appshunter.io/ios/app/universe-size-comparison/id1473946290)

Explore the vastness of space and understand celestial body dimensions through interactive 3D comparisons. Discover the scale of planets and stars, from our Sun to hypergiant stars, with guided tours and free comparison modes.

**Highlights:** 3D astronomical comparisons, Tour Mode with guided explanations, Free Mode for custom comparisons, Scale comparisons of planets and stars, Detailed celestial body information, Elegant user interface

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

**In-app purchases:** none


## Frequently asked questions

### Is Planetary Clock free?

Planetary Clock costs $0.99, with no in-app purchases.

### Is Universe Size Comparison free?

Universe Size Comparison costs $1.99, with no in-app purchases.

### Which has better reviews, Planetary Clock or Universe Size Comparison?

Planetary Clock is rated higher. Planetary Clock averages 4.9 out of 5 from 34 ratings, while Universe Size Comparison averages 3.1 from 29 ratings.

### Do Planetary Clock or Universe Size Comparison have ads?

Neither Planetary Clock nor Universe Size Comparison shows ads.

### Which is updated more often, Planetary Clock or Universe Size Comparison?

Planetary Clock ships an update every 27 months, and Universe Size Comparison every 4 months. Most recently, Planetary Clock was updated on September 30, 2026 and Universe Size Comparison on September 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.*