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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 layers cake, this meant:

Cups needed =((pi x r in2 x .33 in x 2) + (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 leftover, 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 addition 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 naturally grey buttercream frosting made with black cocoa powder

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 use it! Tag me @chelsweets and #chelsweets on social media.

You can also download the charts above here!

Susan

Saturday 7th of May 2022

I love your recipes and tutorials! I am going to be making my daughter's wedding cake, a first for me, and I was planning on making a 4 tier (10, 8,6 & 4 inch) cake. I saw you do this on you "how to make a wedding cake" tutorial but have a question regarding the centre dowel. I see you put one in which went part way up the 6 inch layer, then did you put another dowel in for the top that went down to the middle of the 6 inch cake? My dowel is not long enough to go all the way up to the top layer and not sure if I need to find a longer one or if I can use 2.

Nigel

Sunday 1st of May 2022

Thank you, so helpful

Chanel Rienstra-Roman

Wednesday 9th of March 2022

Hello Chelsea, I recently discovered your website, and your YouTube channel. I appreciate the charts they are extreamly useful. I was also hoping that you could perhaps create a similar type of chart for the amount of filling required for the various size cakes. Thanks You, Chanel

AQ

Friday 18th of February 2022

Hi I am a huge fan of your blog. It is my go to place to find answers to my baking dilemmas. I am attempting a 3 tiered wedding cake and will make your vanilla cake and buttercream recipe. It is going to be a 6", 9" and 12" round wedding cake. From your handy calculators I figured I would need 4 batches of the batter and 26 cups of buttercream. It is going to be decorated with fresh white roses. I just started baking to generate some income and struggle with how much to charge , can you please give me a ballpark figure of what I can charge for this cake. Thanks in advance

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