Enter the diameter and height of the cake into the calculator to determine the required fondant diameter to cover the cake.

Fondant Diameter Formula

The following formula is used to calculate the fondant diameter needed to cover a cake.

FD = CD + (2 * CH)


  • FD is the fondant diameter (inches)
  • CD is the cake diameter (inches)
  • CH is the cake height (inches)

To calculate the fondant diameter, add the cake diameter to twice the cake height. This will give you the total diameter of fondant needed to cover the top and sides of the cake.

What is Fondant Diameter?

Fondant diameter is the measurement of the circle of fondant required to cover the entire surface of a cake, including the top and sides. It is important for bakers to know the correct size of fondant needed to ensure a smooth and complete coverage without excess waste or shortage of material.

How to Calculate Fondant Diameter?

The following steps outline how to calculate the Fondant Diameter.

  1. First, measure the diameter of the cake (CD) in inches.
  2. Next, measure the height of the cake (CH) in inches.
  3. Use the formula FD = CD + (2 * CH) to calculate the fondant diameter.
  4. Finally, calculate the Fondant Diameter (FD) in inches.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

Cake diameter (CD) = 8 inches

Cake height (CH) = 4 inches