# calcMod-Light — modulo calculator

> Modular arithmetic and number theory calculator for factorials, primes, and inverses. (iPhone/iPad app by Alain Cardinaux.)

- Source: https://appshunter.io/ios/app/calcmod-light/id1445360983 (this page in markdown: same URL + `.md`)
- Developer: [Alain Cardinaux](https://appshunter.io/developer/1443066124)
- Category: Education, Productivity
- Price: Free
- Rating: 5.00/5 from 1 App Store ratings · 1 written reviews indexed
- Age rating: 4+
- Requires: iOS 15.0 · 1 MB
- Languages: English
- Released: 2018-12-04
- Data updated: 2026-07-01
- Monetization: free
- User reviews in markdown: https://appshunter.io/ios/app/calcmod-light/id1445360983/reviews.md

## What is calcMod?

What are all the digits of the factorial of 79 and how many digits ?

Want to know if a big integer is prime ? The change mod function indicates when the number is prime.

Want to know the divisors of an integer ? A prime divisor has no inverse modulo this integer.

The "n!" button calculates the factorial of an integer from 0 to 80. Factorial are limited to factorial of 80, but the calculator could calculate them up to 2000 ! (ProX version)

The "change mod" (change modulo) function indicates when the modulo is prime. There is a limit to 10^10 for modulo in this FREE version (no limit with ProX version).

You can stoke one number and recall it when you want.

The "Mod" operation indicates the residue modulo N.

The exp function allow modular exponentiation (as + - *)

The "INV" function calculates the inverse of an integer modulo N.

This app is intended for both mathematics teachers and/or their students, or if you are interested in the beauty of numbers.

Enjoy calcMod-Light !

Les commentaires sont disponibles en français (réglages).

## Key features

- Factorial calculation up to 80!
- Primality testing with change mod function
- Divisor identification
- Modular exponentiation
- Modular inverse calculation
- Number storage and recall

## Recent user reviews (1 of 1)

All indexed reviews: https://appshunter.io/ios/app/calcmod-light/id1445360983/reviews.md

### 5/5 — Would be great to have copy paste functionality

*2021-05-23, version 1.1*

Otherwise great

**Developer response:** Copy will be possible with version 2.0 for iOS 15 😉

## Frequently asked questions about calcMod

### What kind of math problems can calcMod-Light solve?

calcMod-Light can calculate factorials up to 80!, test if large integers are prime, find divisors of integers, and perform modular exponentiation and inverse calculations.

### What is the limit for modulo operations in calcMod-Light?

In the free version of calcMod-Light, there is a limit of 10^10 for modulo operations. The ProX version has no such limit.

### Can calcMod-Light calculate factorials of very large numbers?

The 'n!' button in calcMod-Light calculates factorials of integers from 0 to 80. For larger factorials, up to 2000!, the ProX version is required.

### How does calcMod-Light help identify prime numbers?

The 'change mod' function in calcMod-Light indicates when a modulo is prime, aiding in primality testing of large integers.

### Does calcMod-Light support storing numbers?

Yes, calcMod-Light allows you to store one number and recall it whenever you need it during your calculations.

### What is the age rating for calcMod-Light?

calcMod-Light has an age rating of 4+, making it suitable for a wide range of users.

### On which devices can I use calcMod-Light?

calcMod-Light is currently supported on iPhone and iPod devices.

### How often is calcMod-Light updated?

The latest version of calcMod-Light, 2.0, was released on November 6, 2021. Updates focus on improving functionality and stability.

## Version history (last 3 releases)

### 2.0 — 2021-11-06

- Text display enhancements for iOS 15 and MacOS Monterey (Truncate for big numbers but minimum character size set)
- Possibility to copy the result to the clipboard by clicking on the display!
- Factorial calculation up to 80!

### 1.1 — 2018-12-07

Adjustment of the text on the buttons for small screens.
Optimization of the code.

### 1.0 — 2018-12-03

No release notes.

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## More apps by Alain Cardinaux

- [calcMod-ProX](https://appshunter.io/ios/app/calcmod-prox/id1443066125)
- [calcMod-Blk](https://appshunter.io/ios/app/calcmod-blk/id1445938178)

All apps by Alain Cardinaux: https://appshunter.io/developer/1443066124

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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 2026-07-01.*