the professional unit converter • Free Software • > 6000 units • for Linux, macOS and Windows


Frequenly Asked Questions

General Questions

How famous is the NumericalChameleon ?
The Version 1.6.0 of the NumericalChameleons has been published in many professional IT journals. Many journals have bundled a media. Actually there are more than one million CDs and DVDs where you can find the NumericalChameleon. In addition to that there are more than 100,000 downloads on Nonetheless there are still billions of users out there who have never ever heard about the NumericalChameleon. If you are happy with the application, could you please tell your friends and family about it?

Current download statistics von Sourceforge: Download NumericalChameleon

Which license has been used for the NumericalChameleon ?

The software is copyrighted and it has been released under the conditions of the GPL v3 or later.

Why the GPL ?
The license gives you the freedom to run the program, for any purpose, to study how the program works, and adapt it to your needs, to redistribute copies, and to improve the program, and release your improvements to the public. The GPL guarantees those freedoms, because you are required to license your work under the same license if you adapt the work. 

Is it allowed to redistribute copies of the program (on CD-ROM or DVD)?
Yes, absolutely.

I have a problem with the NC. Can you help me?
Sure, please go to the support section.

Installation Questions

Where can I download this software ?

How do I install this software ?
Please read the installation  instructions.

On my Windows x64 I have installed both a 32 bit JRE and a 64 bit JRE, but the NC always starts with the 32 bit JRE
If you have installed the 32 bit JRE after the 64 bit JRE, the 32 bit JRE will be used since the last installed JRE will win. Solution: install the 64 bit JRE after you have installed the 32 bit JRE. Alternatively you can use jarfix, which you can use to switch between a 32 bit JRE and 64 bit on demand, comfortable and quickly.

I want to use the Java Runtime Environmen from Oracle instead of the Open JDK. How can I do that on Ubuntu ?

Download the JRE from and install it, for example to


Run update-alternatives. See also

$ sudo update-alternatives --install "/usr/bin/java" "java" "/opt/java/jre/latest8/bin/java" 1
$ sudo update-alternatives --config java

If you want to be flexible as possible, you could create /java/jre/64/latest8 just as a symbolic link to the actual Java folder. The advantage would be that each time a new JRE comes out you just have to update the symlink.

Platform Questions

Does the NumericalChameleon run as Portable App as well ?
Yes. You can even choose, whether you want to load not only the program but also the Java Runtime Environment from your USB flash drive. See also the install instructions for the portable NumericalChameleon.

Does the NumericalChameleon also run on my mobile device?
Any mobile computer that supports the Java Standard Edition can run the NumericalChameleon, e.g. Laptops, Notebooks, Netbooks, Tablet-PCs, etc.

Update Questions

The exchange rate update does not find any rates, what's wrong?

Save a webpage to a single file. If you use the Internet Explorer (IE) or Firefox 3.6 or later, select the option "Save as type: Web Page, HTML only" at the dialog called "Save Web Page", otherwise the browser rewrites (destroys) the original HTML of the exchange rate provider and the exchange rate filter (which is based on regular expressions) won't work anymore!
Save as
Alternatively you could also use an alternate web client like wget that stores the web site without modification.

Do you use UMTS? If you use UMTS to connect to the internet, your UMTS provider could optimize the webpages in order to decrease the datatransfer. In that case modified webpages are being delivered to the client. Since the NC requires the original, unmodified webpages, the filters in the NC won't work anymore. You can disable UMTS optimization. Ask your provider how that can be done. Sometimes it helps if you request the webpage a 2nd time (click Ctrl+F5 in IE) before you are going to save a webpage to a file.

Timezones: It seems that the Daylight Saving Time (DST) rules are not up to date
Update to the latest Java Runtime Environment or use the Java Timezone updater.





The Team

The founder of this project is Johann N. Löfflmann from Germany. Since 2001 he has been working with talented people all around the world in order to improve the NumericalChameleon, and learning new areas of knowledge. The list of contributors can always be found in the latest download package and in the copyright section.

GPL v3
OSI certified
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