I'm an app junkie. If there's an app to help do a job, entertain me or educate me, I'll download it (as long as it's free, although I've actually paid for a few apps, too). It's amazing what's out there to use on your smart phone, so it's time to take advantage of those tools and let your phone use its brain a bit!
The University of Illinois Extension an Illinois Council on Best Management Practices have come up with an app that has a calculator to determine optimum nitrogen (N) rates for corn. It also calculates split applications. The Maximum Return to Nitrogen (MRTN) calculator is a regional tool developed by Midwest land-grant universities to help growers calculate the maximum return they will receive from N applications to corn based on prices of N and corn derived directly from research data. The calculator is also available to use via the web. 
“Making the MRTN easily accessible and adding in the flexibility to account for split applications is critical to the ag industry’s goal of maximizing nutrient investment and reducing nutrient losses,” says Dan Schaefer, CBMP’s Director of Nutrient Stewardship. “Partnering with U of I Extension ties in their expertise in promoting use of research and education to benefit agriculture and the environment."
The app allows a grower or certified crop advisor to take the recommended nitrogen rate for the region, choose from various sources of nitrogen, split the applications between fall pre-plant and post-applied, add in stabilizers and calculate the corresponding application costs. A summary of the recommendation can be saved on the phone or tablet for future reference.
I downloaded the app (free!) and found it very easy to use. The calculator buttons were easy to navigate and use, and the options for input were very straightforward. I'd definitely consider this an easy-to-use utility that would be beneficial to farmers. Check it out, download it and play around with it. Might as well take advantage of a free tool that could benefit your farming operation.