# CosmoCalc

> Cosmological distance calculator for astronomers and students. (iPhone/iPad app by Eli Rykoff.)

- Source: https://appshunter.io/ios/app/cosmocalc/id334569654 (this page in markdown: same URL + `.md`)
- Developer: [Eli Rykoff](https://appshunter.io/developer/318275933)
- Category: Education, Utilities
- Price: Free
- Rating: 5.00/5 from 4 App Store ratings · 5 written reviews indexed
- Age rating: 4+
- Requires: iOS 9.0 · 1 MB
- Languages: American English
- Released: 2009-10-13
- Data updated: 2026-06-05
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/cosmocalc/id334569654/reviews.md

## What is CosmoCalc?

CosmoCalc is a simple cosmological distance calculator.  With a simple and intuitive interface you can quickly set a reference cosmology and redshift, and CosmoCalc will calculate a full suite of astronomical distances and scales.

CosmoCalc is a useful and educational reference tool for astronomers, astronomy students, and anybody interested in calculating the distance to astronomical sources.

CosmoCalc allows you to:
* Select cosmological parameters H_0, Ω_m, and Ω_Λ with simple touch-screen controls
* Easily choose from common reference cosmologies, including Planck 2013, WMAP9, Concordance, and Einstein-deSitter
* Quickly determine the luminosity distance, angular diameter distance, lookback time, age of the Universe, comoving volume, and critical density
* Easily switch between flat and non-flat cosmologies by clicking on the chain

## Key features

- 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

## Recent user reviews (5 of 5)

All indexed reviews: https://appshunter.io/ios/app/cosmocalc/id334569654/reviews.md

### 5/5 — Great Tool!

*2023-07-31*

Never will I need to open a Jupyter notebook everytime I want to calculate some simple cosmology things!

### 5/5 — Useful and handy tool

*2014-04-20*

A very handy and useful tool for cosmological calculations. 

It would be more interesting if we can add nonzero curvature and radiation terms. Also the (as of now) hypothetical term with w=-2/3 should be added for fun.

### 5/5 — Cool

*2011-03-23*

Works well

### 4/5 — great tool for being at a seminar

*2011-02-14*

Great tool, I loved it immediately. One important lacking feature is that it doesn't output E(z).

### 5/5 — Very educational

*2010-07-27*

Very esoteric for most, but for the educated layman interested in cosmology, this a a really cool tool.
V2.2 seems to have lost the ability to unchain the total mass/energy sum. Do we have to take as fact that Omega is equal 1?

## Frequently asked questions about CosmoCalc

### What cosmological parameters can I adjust in CosmoCalc?

CosmoCalc allows you to select the Hubble constant (H0), matter density (Ωm), and dark energy density (ΩΛ) using simple touch-screen controls.

### Does CosmoCalc offer different cosmology models?

Yes, CosmoCalc provides options to choose from common reference cosmologies, including Planck 2013, WMAP9, Concordance, and Einstein-deSitter models.

### What types of astronomical distances can CosmoCalc calculate?

CosmoCalc can quickly determine luminosity distance, angular diameter distance, lookback time, age of the Universe, comoving volume, and critical density.

### Is CosmoCalc suitable for beginners in astronomy?

Yes, CosmoCalc is designed with a simple and intuitive interface, making it a useful and educational reference tool for astronomy students and enthusiasts.

### Can CosmoCalc handle both flat and non-flat cosmologies?

Yes, you can easily switch between flat and non-flat cosmologies by interacting with the interface, providing flexibility in your calculations.

### What devices is CosmoCalc available on?

CosmoCalc is supported on iPhone and iPod devices.

### How often is CosmoCalc updated?

The latest version of CosmoCalc is 3.1.1, which was last updated on January 2, 2017. It was initially released on October 13, 2009.

### Does CosmoCalc have ads?

No, CosmoCalc is ad-free, providing an uninterrupted user experience for its educational and scientific calculations.

## Version history (last 5 releases)

### 3.1.1 — 2017-01-02

This app has been updated by Apple to display the Apple Watch app icon.

Finally updated for large screen iPhones! Other small bug fixes, Planck 2015 cosmology, and full iOS 10 compatibility, .

### 3.0 — 2013-09-18

CosmoCalc has been given a complete makeover...inside and out.  Now sporting a snazzy new look for the new iOS!

### 2.4.1 — 2013-03-26

Planck 2013 cosmological parameters are out!  And now available as a default option.

### 2.4 — 2012-09-26

* Support for iPhone 5
* Support for iOS 6
* Defaults to WMAP 7 Cosmology
* VoiceOver Support for visually impaired cosmologists to do "blind cosmology".

### 2.3.1 — 2011-10-22

Fixed bug in distance modulus graph

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## More apps by Eli Rykoff

- [GravLens3](https://appshunter.io/ios/app/gravlens3/id318275930)
- [FVidUp - Flickr Video and Photo Uploader](https://appshunter.io/ios/app/fvidup-flickr-video-and-photo-uploader/id811804075)

All apps by Eli Rykoff: https://appshunter.io/developer/318275933

## Related topics

[eli rykoff](https://appshunter.io/ios/topics/eli-rykoff) · [cosmology app](https://appshunter.io/ios/topics/cosmology-app)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-05.*