There was a download of UnitConvertor-A 2.4.45 on the developer's website when we last checked. We cannot confirm if there is a free download of this software available. The program's installer files are commonly found as conversionA.exe or converter1.exe etc.
We recommend checking the downloaded files with any free antivirus. The actual developer of the software is Institute of Mathematics and Statistics. The most popular version among the program users is 2.4. UnitConvertor-A lies within Office Tools, more precisely Calculators.
From the developer:
UnitConvertor-A is a professional and comprehensive unit-convert computer program. It has very useful interface that is quick in action, easy to use and other distinctive features.
You may want to check out more software, such as Unit Converter Basic, Dovada Calculator or 1-Calc, which might be similar to UnitConvertor-A.