# Formulus — Formulas for Calculus

> A digital reference for essential calculus and math formulas. (iPhone/iPad app by Daniel Byon.)

- Source: https://appshunter.io/ios/app/formulus/id309681983 (this page in markdown: same URL + `.md`)
- Developer: [Daniel Byon](https://appshunter.io/developer/309681721)
- Category: Education, Reference
- Price: $1.99
- Rating: 4.00/5 from 5 App Store ratings · 6 written reviews indexed
- Age rating: 4+
- Requires: iOS 14.0 · 9 MB
- Languages: American English
- Released: 2009-04-01
- Data updated: 2026-06-10
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/formulus/id309681983/reviews.md

## What is Formulus?

Have you ever needed to know that one math formula that you always forget? Do you spend minutes flipping through your textbook or searching the internet for it? Then you need Formulus! 

Formulus is the perfect study tool. It is a simple, easy to use, easy to navigate collection of the most important formulas and topics for high school and college students taking Calculus. 

Includes the following subject areas: 
- Algebra & Geometry 
- Derivatives 
- Functions 
- Integrals 
- Limits
- Logarithms
- Matrices
- Partial Derivatives 
- Series & Sequences 
- Trigonometry 
- Vectors

## Key features

- Calculus formula collection
- Algebra and Geometry formulas
- Derivatives and Integrals
- Limits and Logarithms
- Matrices and Trigonometry
- Vectors and Series

## Recent user reviews (6 of 6)

All indexed reviews: https://appshunter.io/ios/app/formulus/id309681983/reviews.md

### 2/5 — What's with the font size?

*2011-07-14, version 3.0*

Although Formulus is replete with all the formulas I would want, and then some, the screen font sizes are tiny tiny tiny.  barely legible.  And there are no guidelines on using the formulas.  Not even the variables are defined.

I'm not sure who the users are intended to be, but the casual mathematician or scientist, especially one with eyesight issues, will find this app hard to use.

### 5/5 — Easily one of my best buys!

*2010-06-19, version 0*

This app with the latest update rocks! Much easier on the eyes now, still just as functional, even more so now!

Keep up the awesome work :)

### 5/5 — Noting the two errors - still a good app.

*2009-09-07, version 0*

Made a note of the two errors reported, but this is still a very useful app.

### 4/5 — Found another error

*2009-07-20, version 0*

In the complex algebra section, (a+bi)(a-bi) is shown as equalling a*a-b*b (a squared minus b squared). That would be true if not for the fact i*i=-1, making the correct answer a*a+b*b.

I couldn't find a way to submit a comment to the author, either here, nor on his blog. A major oversight on his part, I believe.

### 5/5 — Fast and Efficient

*2009-05-09, version 0*

Great for Differentiating\AntiDifferentiating!

### 3/5 — Found Error

*2009-05-06, version 0*

Hard to get a hold of author. Left blog post on his site but no response. I purchased your product (not the free version). I was showing it to the other students, and I got an approval from my professor to use this during a quiz. He overlooked it and said to not use it now because he caught an error and cautioned me that other errors may exist.

The error he found was in the Algebra & Geometry section, Operations, and its the (a+c)/b = a/b + a/c .

## Frequently asked questions about Formulus

### What subjects does Formulus cover?

Formulus covers a wide range of subjects essential for calculus, including Algebra, Geometry, Derivatives, Functions, Integrals, Limits, Logarithms, Matrices, Partial Derivatives, Series & Sequences, Trigonometry, and Vectors.

### Who is Formulus designed for?

Formulus is specifically designed as a study tool for high school and college students who are taking calculus courses.

### How much does Formulus cost?

Formulus is a paid application, available for a one-time purchase price of $1.99.

### What devices does Formulus support?

Formulus is compatible with iPhone, iPad, and iPod devices.

### When was Formulus last updated?

The latest version of Formulus, 4.0.1, was released on November 19, 2020.

### What is the age rating for Formulus?

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

### How does Formulus help students?

Formulus provides a convenient and easy-to-navigate collection of important math formulas, saving students time they might otherwise spend searching through textbooks or the internet.

### Does Formulus offer any in-app purchases or ads?

Formulus is a paid app and does not feature in-app purchases or advertisements.

## Version history (last 5 releases)

### 4.0.1 — 2020-11-19

Formulus has undergone a complete rewrite. Performance should be much faster, and better adapt to your device.

### 4.0 — 2017-08-01

- Fixed formula sheet errors
- Reorganized formulas

Look out for more future enhancements!

### 3.1.4 — 2015-07-30

- Bug fixes
- Fix for crash on Differential Equations -> Terminology

Formulus Free is now a Universal app! The current iPad-only version of Formulus will be removed from the App Store soon.

### 3.1.3 — 2015-07-29

Formulus is now a Universal app! The current iPad-only version of Formulus will be removed from the App Store soon.

### 3.1.2 — 2015-04-22

Fixed crash related to Differential Equations->Terminology formulas

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All apps by Daniel Byon: https://appshunter.io/developer/309681721

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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 2026-06-10.*