From the developer: "QuickCalc is a tiny, elegant and uniquely useful calculator application which actually calculates as you type. It is the simplest, most useful calculator out there. QuickCalc installs no additional files such as Spyware, VB or MFC Dlls or any other junk, It's simple, clean and really useful. Unlike most downloadable applications, QuickCalc is sanitized and CRC-locked to prevent possibility of virus infection. QuickCalc is tiny, elegant, simple and useful -- just like a software utility should be. Makes a perfect replacement for your Windows Calculator."

Note: QuickCalc will ask you to register only after you have actually used the product for about 45 days (based on actual usage, not calander).