CASTLE BIOSCIENCES INC

(i) Initial Grant for New Directors. Without any further action of the Board, each person who, after the Effective Date, is elected or appointed for the first time to be a Non-Employee Director will automatically, upon the date of his or her initial election or appointment to be a Non-Employee Director (or, if such date is not a market trading day, the first market trading day thereafter), be granted an equity award (the “Initial Grant”) having a value of $350,000400,000, which shall be comprised of a restricted stock unit (“RSU”) award covering shares of common stock. The total number of shares subject to the Initial Grant will be calculated as the value of the Initial Grant divided by the average of the closing prices of the Company’s common stock for each trading day within the 30 calendar days prior to the grant date (such price, the “Average Price”) rounded down to the nearest whole share (the “Total Initial Shares”).

In the event that more than one Non-Employee Director is elected or appointed within a single calendar year, for each Non-Employee Director elected or appointed after the first election or appointment of a Non-Employee Director in such calendar year (each, a “Subsequent Director”), if the Average Price calculated for purposes of determining the Total Initial Shares underlying the Initial Grant for a Subsequent Director has not increased or decreased more than 10% compared to the Average Price calculated for purposes of determining the Total Initial Shares underlying the Initial Grant for the first Non-Employee Director elected or appointed in that same calendar year (the “First Director”), then the Total Initial Shares underlying the Initial Grant for such Subsequent Non-Employee Director shall be equal to the Total Initial Shares calculated for the First Director.

The shares subject to the Initial Grant will vest in a series of three successive equal annual installments over the three-year period measured from the date of grant.

(ii) Annual Grant. Without any further action of the Board, at the close of business on the date of each Annual Meeting of Stockholders following the Effective Date, each person who is then a Non-Employee Director and who has been serving as a Non-Employee Director for at least six months prior to such date will automatically be granted an equity award (the “Annual Grant”) having a value of $250,000260,000 (subject to proration, as described below), which shall be comprised of a RSU award covering shares of common stock. The total number of shares subject to the Annual Grant will be calculated as the value of the Annual Grant divided by the average of the closing prices of the Company’s common stock for each trading day within the 30 calendar days prior to the grant date rounded down to the nearest whole share.

With respect to a Non-Employee Director who, following the Effective Date, was first elected or appointed to the Board on a date other than the date of the Company’s Annual Meeting of Stockholders, upon the Company’s first Annual Meeting of Stockholders following the Non-Employee Director’s first joining the Board, if the Non-Employee Director is entitled to receive an Annual Grant at that meeting, the Annual Grant will be prorated to reflect the number of completed months between the Non-Employee Director’s election or appointment date and the date of that first Annual Meeting of Stockholders. For clarity, if a Non-Employee Director was initially appointed within six months of their first Annual Meeting of Stockholders, then they will not be eligible for that specific Annual Grant.

The shares subject to the Annual Grant will vest in full on the earlier of the (a) one-year anniversary of the date of grant and (b) the day immediately preceding the next Annual Meeting of Stockholders following the date of grant.

(b) Vesting; Change in Control. All vesting is subject to the Non-Employee Director’s Continuous Service (as defined in the Plan) on each applicable vesting date. Notwithstanding the foregoing vesting schedules, for each Non-Employee Director who remains in Continuous Service with the Company until immediately prior to the closing of a Change in Control (as defined in the Plan), the shares subject to his or her then-outstanding equity awards that were granted pursuant to this policy Director Compensation Policy will become fully vested immediately prior to the closing of such Change in Control.

(c) Remaining Terms. The remaining terms and conditions of each award, including transferability, will be as set forth in the Company’s Director Option Grant Package in the form adopted from time to time by the Board.