Income Tax Calculator Mobile App

I am an accountant that needs a mobile application - an Income Tax Calculator to be more specific - to go with a new business venture. I am planning to have the application released in phases and add more functionality to the tax calculator as we go along. Version 1 will be just a simple calculator. The user enters his taxable income into a field and the calculator calculates the tax that he would pay every month and his after tax income. The result of the calculation is compared with last years tax and also shows the current years tax tables. A clean and neat and simple to use app. In later versions we will tax deductions, etc which will complicate the formula behind the scenes and add a couple more fields to the UI. I will provide the developer with the formulas and the logic for the calculation as well as the tax tables or the relevant year. The app needs to be able to run on Andriod and Iphones Looking forward to your proposals. If there are any questions don't hesitate to contact me.