Hi, I'm new to freelancer, but have sufficient programming experience (check out my profile), meaning I can guarantee quality, which I believe a lot of the other bidders cannot. I hope you take my bid into consideration.
First, I have much more experience with developing iPhone applications, so I would prefer to do an iPhone app rather than Android. I also believe that an iPhone Utility app, which is what this would be, can offer a higher level of profitability than Android. However, if you prefer to proceed with Android, I will still be able to help you.
As far as converting an Excel calculator to a smartphone app, I believe this process should be straight forward as long as I am provided with the formulas necessary to do the calculations. I have done a lot of programming in math, so I'm confident that the integration of the formulas into the app will go smoothly.
As for design, I think it would be acceptable to release the app with a basic iOS 7/8 design, in addition to the Launch Screen and App Icon, which I would be able to prepare. If you had other plans for the design of the app, I would be happy to hear them and incorporate them into the app.
If you let me know the details and specs of the app, I could come up with a general layout for the app and have something to show you within a day or two. Please contact me if you have any questions about my proposal or you want to further discuss the application.
Thank you.