| 
             Security 
          Type  | 
          
             Security 
          Class Title  | 
          
             Fee 
          Calculation or Carry Forward Rule  | 
          
             Amount 
          Registered(1)  | 
          
             Proposed 
          Maximum Offering Price Per Share  | 
          
             Maximum 
          Aggregate Offering Price  | 
          
             Fee 
          Rate  | 
          
             Amount of 
          Registration Fee  | 
          
             Carry 
            Forward Form 
          Type  | 
          
             Carry 
            Forward 
            File 
            Number 
           | 
          
             Carry 
          Forward Initial Effective Date  | 
          
             Filing Fee 
          Previously Paid In Connection with Unsold Securities to be Carried Forward  | 
        ||||
| 
             Newly Registered Securities 
           | 
        |||||||||||||||
| 
             Fees to be Paid 
           | 
          
             Equity 
           | 
          
             Common Stock, $0.001 par value per share 
           | 
          
             Other 
           | 
          
             1,282,045(2) 
           | 
          
             $ 
           | 
          
             22.02(3) 
           | 
          
             $ 
           | 
          
             28,230,630.90 
           | 
          
             0.0000927 
           | 
          
             $ 
           | 
          
             2,616 
           | 
          ||||
| 
             Fees Previously Paid 
           | 
          
             — 
           | 
          
             — 
           | 
          
             — 
           | 
          
             — 
           | 
          
             — 
           | 
          
             — 
           | 
          
             — 
           | 
          ||||||||
| 
             Carry Forward Securities 
           | 
        |||||||||||||||
| 
             Carry Forward Securities 
           | 
          
             — 
           | 
          
             — 
           | 
          
             — 
           | 
          
             — 
           | 
          
             — 
           | 
          
             — 
           | 
          
             — 
           | 
          
             — 
           | 
          
             — 
           | 
        ||||||
| 
             Total Offering Amounts 
           | 
          
             $ 
           | 
          
             28,230,630.90 
           | 
          
             $ 
           | 
          
             2,616 
           | 
          |||||||||||
| 
             Total Fees Previously Paid 
           | 
          
             — 
           | 
          ||||||||||||||
| 
             Total Fee Offsets 
           | 
          
             — 
           | 
          ||||||||||||||
| 
             Net Fee Due 
           | 
          
             $ 
           | 
          
             2,616 
           | 
          |||||||||||||
| 
                 (1) 
               | 
              
                 Pursuant to Rule 416 under the Securities Act of 1933, as amended (the “Securities Act”), this registration statement also covers any additional number of shares of Common Stock, $0.001 par value per share
                  (“Common Stock”) of Castle Biosciences, Inc. (the “Registrant”) issuable upon stock splits, stock dividends, or other distribution, recapitalization or similar events with respect to the shares of Common Stock being registered pursuant to
                  this registration statement. 
               | 
            
| 
                 (2) 
               | 
              
                 Consists of an aggregate of 1,282,045 shares of Common Stock, including (i) 699,047 shares issued to the selling stockholders named in the prospectus that forms a part of this registration statement (the
                  “Selling Stockholders”) pursuant to the Agreement and Plan of Merger, dated as of April 4, 2022, by and among the Registrant, Acorn Merger Sub, Inc., AltheaDx, Inc. and Fortis Advisors LLC (the “Merger Agreement”), (ii) 64,840 shares that
                  have been deposited into escrow to support the indemnification obligations of the Selling Stockholders under the Merger Agreement and (iii) 518,158 shares that may become issuable to the Selling Stockholders as milestone payments pursuant
                  to the terms of the Merger Agreement, contingent upon the achievement of certain commercial and regulatory milestone events. 
               | 
            
| 
                 (3) 
               | 
              
                 Estimated solely for the purposes of calculating the registration fee pursuant to Rule 457(c) under the Securities Act, based on the average of the high and low price per share of the Common Stock as
                  reported by the Nasdaq Global Market on June 1, 2022. 
               |