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How Much Buttercream Do I Need?

The age old question…how much buttercream do I need?? For a batch of cupcakes? A 6-inch layer cake? For a wedding cake?!

This post shares everything you need to know to make the perfect amount of frosting for any baking project. It’s basically the frosting version of my cake batter calculator.

The amount of frosting you need varies based on the following factors:

With the help of my buttercream formula and chart below, you’ll be able to figure it out in a snap!

image of a buttercream cake being frosted with sharp edges and smooth sides to show How to Frost a Cake Smoothly

Does It Matter What Type of Buttercream I’m Using?

This guide can be used for pretty much any type of frosting. Whether you’re using American, Swiss, Italian, Russian, or even German, a cup of frosting is a cup of frosting.

My only note on this is that I find I sometimes need a tiny bit more American buttercream to make a perfectly smooth cake.

If I’m using a meringue-based frosting, it usually is a bit easier to smooth and I can use slightly less on the sides of the cake.

How Does this Buttercream Calculator Work?

Creating this chart meant thinking through what we’re trying to calculate.

To know how much frosting we’ll need, we need to use the formula of a cylinder, the formula of a circle, and then back out how many cubic inches are in a cup to get to our answer.

With that in mind, the formula I used is:

Cups Needed = ((area of a circle x thickness of the layer of frosting x number of layers) + (surface area of a cylinder minus top and bottom)) / by cubic inches per cup

Or in terms of numbers for a 6-inch, 2-layer cake, this meant:

Cups needed =((pi x r in2 x .33 in) + (2 x pi x r in x h in x .25 in))/14.4 in3

I had to make some assumptions in this formula, including that the outer coat of frosting will be about 1/4 inch thick, and that the frosting layers inside the cake will be about 1/3 inch thick.

This is based on how I actually decorate my cakes! I love thick layers of frosting inside, just like in my death by chocolate cake shown above.

However, if you use a lot less frosting between your cake layers, or if you want to make a design that requires a lot of extra buttercream (like buttercream rosettes) these numbers might need to be adjusted.

If you aren’t a big fan of math, don’t worry! I’ve used this formula to create a chart below that’s super easy to use. It’ll instantly tell you how much buttercream you need 🙂

Step 1: How Big is the Cake You’re Making?

The size, shape, and number of cake layers will impact how much frosting you need.

In general, I find one batch or about 6 cups of frosting is the perfect amount for a 7-inch or 8-inch layer cake that’s decorated with buttercream swirls on top.

I usually have a tiny bit left over, but it’s just about right. This makes sense based on my calculations below!

image of a gluten free funfetti cake that's been decorating with buttercream stripes and a pink drip

Step 2: Use My Buttercream Calculator to Figure Out How Much Frosting You Need

Based on the size of your cake, use the charts below to figure out how much frosting you need. This is just to fill, crumb coat, and cover a layer cake.

Add an additional 1-2 cups of frosting to the numbers below if you want to pipe large buttercream swirls on top of the cake.

Or if you want to make a frosting-intensive design like covering a cake in buttercream rosettes, add an additional 2-3 cups of frosting for a cake ranging from 6-8 inches. It sounds insane, but those designs require so much extra frosting!

image of a chart showing how much buttercream you need to frost a round layer cake
image of a chart showing how much buttercream you need to frost a square layer cake
image of a chart showing how much buttercream you need to frost a cupcakes

Step 3: How Many Cups of Buttercream are in One Batch of Buttercream?

Now you just need to figure out how many cups of frosting one batch makes.

My American and Swiss Meringue buttercream recipes both make about 6 cups of frosting.

image of purple frosting in a bowl that's been stirred by hand to make it super smooth after it had developed air bubbles from sitting

However, it can vary based on the recipe you’re using.

Most recipe cards list the yield at the top of the recipe card or will share it in the notes section at the bottom of the recipe card.

Now that you know how many cups of frosting you need, you can back into how many batches of frosting you’ll need to make.

And just like that, you’re ready to make the perfect amount of frosting!!

I’d love to hear if you found this post helpful, or if you end up using it! Tag me @chelsweets and #chelsweets on social media.

You can also download the charts above here!

Dona

Sunday 25th of February 2024

Great, thanks for the amounts, now where is your recipe for buttercream frosting.. Novice baker, need a simple recipe with enough to make a ribbon around the top. THankyou.

Dorothy

Sunday 14th of January 2024

I love the volume of frosting you use between layers, but I can never seem to get it right or consistent. Do you know approximately how much you you put between layers on an 8" cake?

Chelsweets

Sunday 14th of January 2024

Hi Dorothy,

I am always very generous and use a few big spatula scoops! My method isn't very scientific, but I know some bakers who use a big cookie scoop and add a set number of scoops to keep the frosting between the layers perfectly consistent. I'd recommend giving that method a try! Hope that helps, happy baking!

Chocolate Cinnamon Cream Cheese Frosting - Liv's Little Muffins

Friday 29th of December 2023

[…] sheet cake with this amount. For other sizes or layer amounts, I highly recommend checking out Chelsweets buttercream calculator. It’s a great easy tool and she has everything you can think of in this […]

Denise

Thursday 19th of October 2023

I’m making a 7” base Barbie dress cake (for the first time) with a 2 layer 10” cake under it. I want to completely cover both with rosettes. Dress is one color, base another color. How many batches of your vanilla buttercream will I need?

Chelsweets

Sunday 22nd of October 2023

Hi Denise,

That is a unique shape / size combination! I'm assuming you'll also need buttercream to fill and crumb coat those cake layers? With that in mind, I'd guess you'd need at least 3 batches, if not 4!

Kathy Harris

Wednesday 2nd of August 2023

Hi Chelsea, I am using your chart to determine how much frosting I need for my daughter’s wedding cake. I wonder how much I should reduce, in cups, for a semi-naked cake?

Thank you for your input! I love your website and tutorial videos!

Chelsweets

Thursday 17th of August 2023

Hi Kathy,

You'd need about half the frosting that the chart recommends for a semi naked cake. Hope that helps, happy baking!