title: How to summarize a formula field in crystal reports?
body: <p>How do I add a running total or summary field on a formula field in crystal reports? </p>
  
  <pre><code>// Sample Report
  
   Serial No.       Premium        Commission         Net (Premium-Commission)
  -----------------------------------------------------------------------------
      1.              10               4                    6        
      2.              40              30                   10
    ---------------------------------------------------------------------------
    Grand Total       50              34                   16
  </code></pre>
  
  <p>In sample report, Net (Premium-Commission) is a formula field which gets evaluated for each row? How do I add a grand total/summary field for my formula?  It seems we can add a summary field to only <code>Command fields.</code></p>