Not as clumsy or random as a computer
... an elegant instrument for a more civilized age ...
(Obi-Wan Kenobi)
(last update: 11th March 2020)

Collection of Slide Rule replicas

Slide rules are not manufactured anymore.
The ones, which still exist, will eventually deteriorate with time.
Here you will find a collection of some of the most prominent models carefully hand-crafted and simulated (or emulated) in JavaScript.

It is a Slide Rule Simulator or Emulator

All the scales are programmatically drawn based on reverse enginered mathematical equations.
As such, no images are used for visualisation (only some decorations).
And this is why those simulations are of the highest quality.
This is also why the word "replica" is quite appropriate for those simulations.

All the replicas can be yours right now, totally free.
All you need to do is to download the whole lot and they are yours forever.

(Technical information: all replicas can work without any active internet connection and as such, they are digitally safe. The code is hosted on

In random order:



Hemmi / Post



Keuffel & Esser




Flying Fish


Zvi Doron

Michael O'Leary


Quick manual

.... but how do you use a slide rule anyway?

Some of the replicas carry an interactive tutorial, where you can also practice using a slide rule. In particular, you can use the Raven and the Templar for learning.
However, there is also a training game included, where you are required to pass some slide rule tests.
As you progress through the tests new and more complex slide rules are available for you to practice.
The game is accompanied by completely fabricated stories, just for fun.

There are also numerous tutorials freely available online.


You can CONTACT the author (Dr Robert P. Wolf), through his HERCs Music Systems page.

Mailing List

If you are a fan or a collector of slide rules, or if you just wish to talk about all matters regarding this beautiful tool, then you may wish to join our mailing list.


Oughtred Society Sliderule Museum

A sample simulation of Faber-Castell 2/83N replica can be viewed below.