iPad Screenshots


Have you ever used a slide rule? Ever been curious about the way slide rules can be used to solve complex math expressions? Would you like to learn how slide rules work? Slide rules were used for literally hundreds of years before calculators and in some regards can be much more useful than calculators.

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

There are 80 different scales in iSlideRuleHD. 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. Additionally, a two-finger pan on the slide allows seeing either the left or right index.

The application supports all orientations, rotating the slide rule to take full advantage of the display, and has 11 selectable 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.

What's New

Version 2.2.0

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

Ratings and Reviews

Awesome App


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.

Fix the slide!

Cancer Doc

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.



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.


Stephen Reid
14.1 MB
Requires iOS 7.1 or later. Compatible with iPad.
English, Dutch, French, German, Greek, Italian, Japanese, Portuguese, Russian, Spanish, Swedish, Thai, Turkish
Age Rating
Rated 4+
© 2011-2015 Reid Performance Designs, All Rights Reserved.


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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