# iSlideRuleHD — Fully customizable sliderule

> Digital slide rule app with extensive mathematical functions and customizable scales. (iPhone/iPad app by Reid Performance Designs.)

- Source: https://appshunter.io/ios/app/isliderulehd/id473519866 (this page in markdown: same URL + `.md`)
- Developer: [Reid Performance Designs](https://appshunter.io/developer/292884536)
- Category: Education, Utilities
- Price: $0.99
- Rating: 4.50/5 from 2 App Store ratings · 8 written reviews indexed
- Age rating: 4+
- Requires: iOS 9.2 · 35 MB
- Languages: American English, Dutch, French (France), German (Germany), Greek, Italian, Japanese, European Portuguese, Russian, European Spanish and 3 more
- Released: 2011-10-21
- Data updated: 2026-06-10
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/isliderulehd/id473519866/reviews.md

## What is iSlideRuleHD?

iSlideRuleHD is a fully configurable sliderule app supporting multiplication, sines, tangents, cosines, cotangents, roots, squares, logarithms, and hyperbolics.

There are nearly 100 different scales in iSlideRuleHD, including scales that support dimensional analysis. From the scales provided, 15 can be selected for the top and bottom rules, as well as the slide, in groups of 5 scales each. Double-tapping each rule selects the next group of 5 within the application. A two-finger pan left or right on the center slide allows viewing either the left or right index of the body. 

The application supports all orientations, rotating the slide rule to take full advantage of the display, and has multiple color schemes to customize your slide rule to your favorite color.  A single-finger swipe on the cursor up or down dynamically changes the color scheme.

## Key features

- Multiplication, sines, tangents, cosines, cotangents
- Roots, squares, logarithms, hyperbolics
- Nearly 100 different scales
- Customizable top, bottom, and slide rules
- Multiple color schemes
- Supports all orientations

## Recent user reviews (8 of 8)

All indexed reviews: https://appshunter.io/ios/app/isliderulehd/id473519866/reviews.md

### 4/5 — Good App; small error

*2020-09-25, version 3.0.0*

A fun rule to experiment with, given the multitude of scales you can set up. However, one thing I noticed is that the CIF scale is out of position relative to the other scales, whether it is on the slide or the stator, resulting in an error in calculations.

### 4/5 — Hard to beat for free!

*2019-05-19*

This is a wonderful introduction into what a slide rue can do and it is a great way to have one with you without the risk of it being damaged. Slide rules are not cheap today, as if the really ever were. Carrying one about can be a risk. Mine are very important to me. I do not want anything to happen to them so having one in the iPad is a significant boon. No it isn’t perfect, but then, it’s FREE!

### 5/5 — Excellent tool for teaching math!

*2015-06-18*

Stop being lazy, and learn how to visualize numbers with a slide rule!

### 5/5 — The definitive slide rule app

*2015-02-28*

Works exactly as described.  Effective and intuitive interface, good use of screen space and touch controls.  Sharp and clear scales.  Nice customisation with scale options and colours.  Actively updated.  Most importantly, usable as an actual slide rule.

### 3/5 — Fix the slide!

*2013-09-30*

I have most of the slide rule apps. This one has much to recommend it. The size makes it easy to see and enhances the accuracy. I also like the numeric readings at the hairline. It is fully customizable to match most rules out there and it seems accurate.  The problem is the slide is independent of the body. I move the slide to where I want it, then move the body and the slide doesn't go with it! You have to move the cursor to keep the slide in position. It's just not natural. When the body is moved, the slide must move with it. Period. Fix that and I'll give it five stars.

### 3/5 — Works as described

*2013-04-26, version 1.0.2*

The app basically works as described. I'm not a big fan of the "non-physical" behaviour of the cursor (it stays behind when you move the top and bottom rules); the user interface is non-intuitive, which is kind of strange for a slide rule.

There's a nudge feature that lets you fine-tune the slide position. Unfortunately, it seems to have a bug in landscape mode - you can only nudge in one direction.

### 5/5 — Mr.

*2013-03-15*

This is a great product for those who love slide rules and the slide rule's ability to enhance the learning process for mathematics.  The ability to customize so many different (70+) scales in groups of five is very impressive.  The attention to detail for the gage points (key constants such as pi, e, unit conversions, etc.) shows a deep appreciation for the art.

### 5/5 — Awesome App

*2012-06-01*

This is a beautifully done app, very professional looking. It basically allows you to transfer almost any combination of slide rules to the iPad, from the simplest ones to the most complicated log-log rules as well as to invent your own unique rules. the interface is very simple and elegant and is actually even easier to use than a physical slide rule. it looks stunning on the retina display. About the only feature I would like to see added is the ability to remember the slide rule state (cursor and slide positions) when reopening the app. Kudos to the developer. I have seen many slide rule apps over the years and none even approaches the look and utility of this one. it allows you to do things that would be cumbersome to program on a calculator and the displaying of the decimal values alongside the cursor makes it very practical for real-world calculations.

## Frequently asked questions about iSlideRuleHD

### What mathematical functions does iSlideRuleHD support?

iSlideRuleHD supports multiplication, sines, tangents, cosines, cotangents, roots, squares, logarithms, and hyperbolics. It offers nearly 100 different scales for dimensional analysis and advanced calculations.

### How can I customize the scales on iSlideRuleHD?

You can select from 15 different scales for the top and bottom rules, as well as the slide, in groups of 5 scales each. Double-tapping each rule cycles through these groups.

### Does iSlideRuleHD have ads?

No, iSlideRuleHD is ad-free. It is a paid application that provides an uninterrupted user experience for its mathematical functions.

### What devices is iSlideRuleHD compatible with?

iSlideRuleHD is currently supported on iPads. It is designed to take full advantage of the larger display for its slide rule functionality.

### How often is iSlideRuleHD updated?

The latest version, 3.1.1, was released on April 14, 2022. Updates typically include improvements and new features based on user feedback and technological advancements.

### What is the user sentiment for iSlideRuleHD?

The app has a high rating of 4.5 stars from 2 ratings, indicating positive user sentiment. Users appreciate its functionality and customization options.

### Can I change the appearance of iSlideRuleHD?

Yes, iSlideRuleHD features multiple color schemes to personalize your slide rule. A single-finger swipe on the cursor up or down dynamically changes the color scheme.

### What is the age rating for iSlideRuleHD?

iSlideRuleHD has an age rating of 4+. This indicates it is suitable for users of all ages, with no mature content.

## Version history (last 5 releases)

### 3.1.1 — 2022-04-14

Updated handling of initial user default settings

### 3.1.0 — 2022-04-09

Updated CIF and DIF scales to correct an offset error.
Added new ES and Faber-Castell scale coloring options.
Added iSTd, X/theta, N1-N4 and 1/N1-1/N4 scales as well as Th and Ch hyperbolic trig scales.
Migrated documentation from within the app to website-based.

### 3.0.0 — 2019-02-25

Updated errors in the integrated help documents. Updated app to provide better support of latest iOS versions, as well as newer device models.

### 2.2.0 — 2015-08-11

Added ability to change settings within the application.
Removed application from the built-in Settings.

### 2.1.0 — 2015-03-26

Added feature to lock the slide to the body when body is moved, enabled by default.
Updated user documentation with latest information
Improved positioning and accuracy of number display on cursor
Improved "nudge" feature for finer tuning of positions.
Corrected descriptions for the inverse log scales

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## More apps by Reid Performance Designs

- [iSlideRule](https://appshunter.io/ios/app/isliderule/id292884533)

All apps by Reid Performance Designs: https://appshunter.io/developer/292884536

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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.*