For professional bakers and cake decorators, eyeballing the amount of fondant needed to cover a specific cake may be easy.
However, it can be highly confusing if you’re new to this field. So, how to know exactly how much fondant you should prepare to cover a cake?
To be honest, it’s not an exact science. Contrarily, it depends on many factors, such as the size and shape of the cake, along with how thin you can roll your fondant.
In this article, I’ve prepared a quick guide with the most common cake shapes and how much fondant each size requires. So, keep reading.
How Much Fondant Do You Need to Cover a Cake
Calculating the amount of fondant you need can be tricky. It differs according to your ability to roll out the fondant to the exact shape and thickness.
It may also depend on how much excess fondant you like to trim out after covering your cake.
The following guide gives an estimate of how much fondant to use for each cake shape. Using it, you end up with roughly half an inch of extra fondant at the edges to cut off.
Note: The following information is based on a fondant thickness of around ⅛ inches (3–5mm).
Round Cakes
The round shape is one of the most common and most popular among all cakes, whether for a wedding or a birthday party.
It’s also a versatile shape that allows you to create stunning formations, from single to multi-tiered designs.
Commonly, wedding cakes have at least two to four tiers. Each tier consists of two to four layers with fillings in between.
Typically, the number of layers affects the overall cake height. In turn, it also affects the amount of fondant to cover it.
In general, round cakes vary in size from 6 to 18 inches. As for the height, they’re usually either three or four inches high.
Here’s a table showing the most common round cake sizes and how much fondant coverage it requires.
| Cake Size | Fondant Amount |
| 3-inch High Round Cake | |
| 6 inches | 14 ounces (397 grams) |
| 8 inches | 18 ounces (510 grams) |
| 10 inches | 24 ounces (680 grams) |
| 12 inches | 36 ounces (1020 grams) |
| 14 inches | 48 ounces (1360 grams) |
| 16 inches | 72 ounces (2041 grams) |
| 18 inches | 108 ounces (3062 grams) |
| 4-inch High Round Cake | |
| 6 inches | 18 ounces (510 grams) |
| 8 inches | 24 ounces (680 grams) |
| 10 inches | 36 ounces (1020 grams) |
| 12 inches | 48 ounces (1360 grams) |
| 14 inches | 72 ounces (2041 grams) |
| 16 inches | 108 ounces (3062 grams) |
| 18 inches | 140 ounces (3969 grams) |
Square Cakes
Although round cakes have a more classical look, square cakes are also popular among people for their edgy and unique designs.
They’re also practical because they can serve a much larger crowd, making them a great option for huge weddings.
That said, square cakes are often more costly than round cakes. That’s mainly because of the time-consuming techniques they require to cover with fondant.
In all cases, square cakes come in various sizes, from 6 to 16 inches. With that in mind, take a look at the following table showing the amount of fondant needed for each size.
| Cake Size | Fondant Amount |
| 4-inch High Square Cake | |
| 6 inches | 24 ounces (680 grams) |
| 8 inches | 36 ounces (1020 grams) |
| 10 inches | 48 ounces (1360 grams) |
| 12 inches | 72 ounces (2041 grams) |
| 14 inches | 96 ounces (2721 grams) |
| 16 inches | 120 ounces (3402 grams) |
Heart Cakes
Although not as common as the other shapes, heart cakes have their occasions. They can be perfect for Valentine’s Day, Mother’s Day, an engagement party, or a couple’s anniversary.
A four-inch high, heart-shaped cake requires the following amount of fondant to cover it.
| Cake Size | Fondant Amount |
| 4-inch High Heart Cake | |
| 6 inches | 18 ounces (510 grams) |
| 8 inches | 26 ounces (737 grams) |
| 9 inches | 32 ounces (907 grams) |
| 10 inches | 36 ounces (1021 grams) |
| 12 inches | 48 ounces (1361 grams) |
| 14 inches | 72 ounces (2041 grams) |
| 15 inches | 72 ounces (2041 grams) |
| 16 inches | 96 ounces (2722 grams) |
Oval Cakes
Cakes aren’t all round and square. Sometimes, you find yourself in a situation where you need to decorate an oval cake.
Many custom cake designs require an oval base, such as cartoon cakes. That’s why you need the following table to know how much fondant to use to cover such a shape.
| Cake Size | Fondant Amount |
| 4-inch High Oval Cake | |
| 7 3/4 x 5 5/8 inches | 24 ounces (680 grams) |
| 10 3/4 x 7 7/8 inches | 48 ounces (1361 grams) |
| 13 x 9 7/8 inches | 48 ounces (1361 grams) |
| 16 1/2 x 12 3/8 inches | 72 ounces (2041 grams) |
Hexagon Cakes
This is one of the least common cake shapes. However, hexagon cakes can add a special touch to a multi-tiered cake.
Whether the cake is all hexagon-shaped or incorporated with round tiers, the final result is always mesmerizing.
Just remember to practice covering such shapes with fondant a couple of times before getting to business, as it can be tricky.
Check out the following table with the amounts of fondant you need to cover a hexagon cake.
| Cake Size | Fondant Amount |
| 4-inch High Hexagon Cake | |
| 6 inches | 18 ounces (510 grams) |
| 9 inches | 36 ounces (1021 grams) |
| 12 inches | 48 ounces (1361 grams) |
| 15 inches | 84 ounces (2381 grams) |
Pillow Cakes
The last cake shape to cover in this article is the pillow one. Though the least common, you can use this shape to make stunning designs for various occasions.
From baby showers to baptisms, a pillow cake can always be a showstopper.
Here’s a table showing the amount of fondant you need to cover a pillow cake.
| Cake Size | Fondant Amount |
| 4-inch High Pillow Cake | |
| 6 3/4 x 6 3/4 inches | 16 ounces (454 grams) |
| 10 x 10 inches | 28 ounces (794 grams) |
| 13 1/4 x 13 1/4 inches | 48 ounces (1361 grams) |
Final Thoughts
Covering cakes with fondant provides optimal space for you to go wild with the decorations. It also gives the cake a smooth and elegant finish.
Sometimes it can be tough to tell how much fondant you need to cover a particular cake shape. Yet, with the help of this article, it’ll never be an issue.
In all cases, rolling out fondant can be tricky. So, don’t overlook the importance of practice.
Sarah is the founder of Baking Kneads, LLC, a blog sharing guides, tips, and recipes for those learning how to bake. Growing up as the daughter of a baker, she spent much of her childhood learning the basics in a local bakery.