Wordpress calculation widget

Hi

I would like a custom wordpress widget, that can make a calculation from two different inputs, that can be placed in a sidebar. Very similar to the Mortgage Loan Calculator, BMI Calculator or Price Calculator widgets that are available.

The two inputs are going to be Power in Watts and Voltage in Volts. The calculation is then going to be

power = power * (1+((240-Voltage)/100))

result = ((1/(1-((1-(power/669))*1.4)))-1)*100

and then it rounds it to two decimal places

Ideally the widget will allow for some text to be placed above and below the inputs and the result.

Thanks

Phil