CompPad

CompPad allows you to create technical calculations in the form of conventional-looking mathematical expressions using the LibreOffice equation editor. This editor has a simple text syntax that some consider to be faster and more intuitive than other equation editors. Then, with the click of a toolbar icon, CompPad will evaluate the expressions and display the results, embedded in your document. All of the features of LibreOffice are available for documenting and formatting your document so that it can be presented with pride to co-workers, customers, professors, etc.

Example

Here is an example of how you might use CompPad. It is a simple mechanical harmonic oscillator example based on the Wikipedia topic . You can download this example here: example - harmonic oscillator.odt.

• Install the CompPad extension (easy, see below.)
• Open a new LibreOffice Writer document. You should see a toolbar that looks like this: .
• First we define the mass of the oscillator. Enter the following text in the toolbar edit field : (without quotation marks) "M:=10 kg"
• Press "enter" or click . The following formula will be created:
  
• Use the mouse to move the cursor to a point after the formula. Now you can create another formula or edit text.
• Define the spring constant: "K:= 4 lbf/inch"
  
• Calculate the natural frequency of the oscillator: "f_n := 1 over {2 %pi} sqrt{ K over M}="
  
• To evaluate the expressions you've entered so far, click . You will see that the last expression gets updated with the result of the calculation:
  
  Notice how the units of measure were handled automatically. Even though we entered quantities in both SI and US Customary units, the correct solution was computed.
• Define the amplitude of the oscillation: "A:= 2 cm"
  
• Define position as a function of time: "x(t) := A cos left( sqrt{K over M } t right)"
  
• Create a time vector with 21 elements, ranging from 0 to 1 s: "t:={0 dotslow 20} over 20 s"
  
• Then calculate the position vector: x_t:= x(t)
  
• To plot position vs. time: "plotxy(t,x_t)"
• Finally, click . You will see the following plot added to the document:
  
  

Now, you can add text, pictures, formatting, and other elements using all of the features of LibreOffice Writer. If you need to change a parameter in the calculation, you can make your changes using the equation editor, and then to re-evaluate the document.

CompPadDemo.odt demonstrates all the features of CompPad in a writer document. Also, check out the example files.

Screenshots

Installation

• All releases are available HERE.
• New users should download the most recent .oxt from "0.5" - this is the current release and the default download.
• The older Java-based releases remain available under "Stable" if you need them.
• In LibreOffice, installing the extension for the first time should be as simple as opening the .oxt file using "File" -> "Open", or via "Tools" -> "Extension Manager".
• After installing, you will need to re-start LibreOffice.
• If you are upgrading from a previous version of CompPad, the above procedure may work. However, if it fails, ask on the Discussion Forum

The current release (0.5.03) is implemented in Python and requires no Java runtime - it uses the Python scripting support built into LibreOffice, and has been tested with LibreOffice 26.2. It should run on Windows, Linux, macOS, and other operating systems that support LibreOffice.

The legacy 0.4.x releases under "Stable" are implemented in Java and require Java 11.

Using CompPad

• Try the example above
• For a document with an extensive list of examples, download CompPadDemo.odt . This file demonstrates most of the features of CompPad and should help you get started.
• Try changing the expressions in these examples, or create a new document with your own expressions. If you get an error, double-check the offending formula.
• If you're stuck, search the Discussion Forum to see if your question has already been answered.
• Post questions, bug-reports and feature requests to the Discussion Forum .

Example Files

CompPadDemo.odt is a document which contains examples of most CompPad features.

example - fluid mechanics.odt

Current Status

CompPad is usable and has been reportedly used to evaluate documents with hundreds of formulas.

Here are a few of the features that are supported in the most recent version:

• Single-line function definition
• Quick editing of formulas using edit field in tool-bar.
• Real and Complex numbers, booleans, vectors and matrices
• Units of measure are handled in all quantities and calculations.
• Units are displayed according to the specified system of units. Options are "SI","US","CGS".
• Support for alternate decimal separators - either "." or ","
• Basic operators including arithmetical, exponential, comparison, rounding, trigonometric, logarithmic, exponential..
• Vector / matrix operators including transpose, multiply, Min, max, sum, product. Scalar operators can also be applied to vectors.
• Basic X-Y plotting
• Complex variable names consisting of almost any combination of text or formula element.
• Changing expression color
• Blocking evaluation of an expression.
• Setting number of displayed significant figures or decimal places.
• import expressions from a text file.

If you require a certain feature for CompPad to be useful to you, please let me know. I may be able to give it priority.

Development

CompPad is being actively developed.

Following are a few features I hope to implement eventually:

• Import expressions from other documents
• Read from and write to cells in LibreOffice Calc.
• Solve blocks
• Function blocks
• Control stuctures (do-loops, if-then-else, etc.)
• More complete set of built-in functions and operators, including integrals and derivatives.
• Symbolic operations, using Maxima as a symbolic engine
• Localization
• Plug-in framework for adding new functions, operators, etc.
• Web interface

Contribute

Currently the best way to contribute is to try out CompPad, and post your question and comments to the Discussion Forum. Your comments help me know what is important to users. I would especially like to know how you would like to use CompPad. If you require a certain feature in order for CompPad to be useful to you, then let me know. I may be able to give it priority.

License

Source code is provided under the terms of the GPL Ver. 3. It is available through GIT on the Sourceforge Project Page.

Copyright 2026. All Rights Reserved.