Plant Available Nitrogen (PAN) Conversion Chart
Use this formula to calculate how much Nitrogen will be available to your plants or crop during the growing season. There are huge differences between fertilizers based upon the Carbo to Nitrogen (C:N) ratio. The higher the ratio, the lower the available Nitrogen. Variances range from 50% to almost 100% for organic fertilizers.
Following is an Excel spreadsheet for your use which will allow you to input your variables such as Carbon and Nitrogen Content, and quantity of fertilizer to be applied and the formulas will calculate your PAN