# Corn N Rate Calculator > Calculates optimal nitrogen fertilizer rates for corn to maximize farm profitability. (iPhone/iPad app by UW-Madison Integrated Pest Management program.) - Source: https://appshunter.io/ios/app/corn-n-rate-calculator/id455298473 (this page in markdown: same URL + `.md`) - Developer: [UW-Madison Integrated Pest Management program](https://appshunter.io/developer/455090091) - Category: Utilities, Business - Price: Free - Rating: 5.00/5 from 1 App Store ratings · 1 written reviews indexed - Age rating: 4+ - Requires: iOS 16.0 · 1 MB - Languages: American English - Released: 2011-08-19 - Data updated: 2026-06-10 - Monetization: free - User reviews in markdown: https://appshunter.io/ios/app/corn-n-rate-calculator/id455298473/reviews.md ## What is Corn N Rate Calculator? This app is designed to assist producers in selecting a Nitrogen (N) rate that improves profitability when N and corn prices fluctuate. Maximum return to N (MRTN) is the N rate that will be most profitable for a particular N:Corn price ratio. The MRTN rate is the LARGE number expressed in lbs N/acre at the bottom of the screen, and is the total N rate recommended for your field. From this number, you need to subtract the lbs N/acre starter you apply and subtract the lbs N/acre N credits you take. Below the single large number is the range of N rates that result in profitability within $1/acre of the MRTN rate. ## Key features - Calculates Maximum Return to Nitrogen (MRTN) rate - Adjusts for fluctuating N and corn prices - Provides a range of profitable N rates - Assists in selecting optimal fertilizer application ## Recent user reviews (1 of 1) All indexed reviews: https://appshunter.io/ios/app/corn-n-rate-calculator/id455298473/reviews.md ### 5/5 — Supports iPad *2011-08-30* Thanks for the update! Works great now. I really like the ability to email the report (also in the N Price Calculator). This is the first Ag based calculator type app that I seen that feature. Good idea and it works as advertised. ## Frequently asked questions about Corn N Rate Calculator ### What is the Corn N Rate Calculator? The Corn N Rate Calculator is a free utility app designed to help corn producers determine the most profitable nitrogen fertilizer rate based on current nitrogen and corn prices. It calculates the Maximum Return to Nitrogen (MRTN) rate. ### How does Corn N Rate Calculator help with profitability? By calculating the MRTN rate, the app identifies the nitrogen application amount that yields the highest profit for a given price ratio of nitrogen to corn. It also shows a range of rates that are nearly as profitable. ### Does Corn N Rate Calculator have ads? No, the Corn N Rate Calculator is ad-free. It is a free utility application with no advertisements present. ### What devices is Corn N Rate Calculator available on? Corn N Rate Calculator is available for iPhone and iPad devices. It is designed for iOS users. ### How often is Corn N Rate Calculator updated? The latest version of Corn N Rate Calculator is 2.12, which was last updated on November 18, 2022. This indicates a relatively infrequent update cycle. ### What is the age rating for Corn N Rate Calculator? Corn N Rate Calculator has an age rating of 4+. This means it is suitable for users of all ages. ### Who developed Corn N Rate Calculator? Corn N Rate Calculator was developed by the UW-Madison Integrated Pest Management program, an organization focused on agricultural research and extension. ### What is the user rating for Corn N Rate Calculator? Corn N Rate Calculator has a perfect rating of 5.0 stars based on 1 review. This suggests a highly positive user experience from its limited feedback. ## Version history (last 5 releases) ### 2.12 — 2022-11-18 User interface updates for iOS 16 ### 2.11.1 — 2022-02-14 Bug fix for text input fields. ### 2.11 — 2020-07-24 Update for newer IOS Versions. Minor bug fixes ### 2.0 — 2017-08-13 The interface as been updated and redesigned to work well on all screen sizes and devices. ### 1.3 — 2013-11-10 - Updated for iOS 7 ## More apps by UW-Madison Integrated Pest Management program - [N Price Calculator](https://appshunter.io/ios/app/n-price-calculator/id455090088) - [IPM Toolkit](https://appshunter.io/ios/app/ipm-toolkit/id504685615) - [Crop Calculators](https://appshunter.io/ios/app/crop-calculators/id692861569) - [NPK Credits](https://appshunter.io/ios/app/npk-credits/id954888966) - [Bean Cam](https://appshunter.io/ios/app/bean-cam/id1072670653) All apps by UW-Madison Integrated Pest Management program: https://appshunter.io/developer/455090091 --- *Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-10.*