If you are looking for a simple, light application that needs no installation to do financial calculations, you`ve found it. It is called Finanx FX12C, an excellent tool to do complex calculations on the PC. Finanx FX12C is the virtual version of the HP–12c calculator. Finanx FX12C accepts keyboard shortcuts, which save time when making calculations, as you have no need of the mouse.
The resources are basically the same as you would find in a calculator (in its physical version), with functions to calculate loans, do accounting on your bank accounts, calculate your cash reserves, etc.
A good tool that helps you in tasks related to finance.