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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!

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!


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!


Tuesday 27th of June 2023

Hi Chelsea, Thank you so much for the formula. I was trying to compute how much filling vs. frosting as I am going to fill with a different buttercream. I used the formulas you gave (Thanks for this) then spent several minutes trying to figure out why my numbers were lower than yours I finally realized that you are multiplying by the number of layers for the filling calculation as opposed to (number of layers -1) which is effectively the number of filling layers. I will use your formula to be on the safe side and since it is tried and true. When I use the number of cake layers instead of filling layers, my frosting + filling cups match yours. I really appreciate your thorough explanation.


Monday 3rd of July 2023

Hi Sylvie,

Amazing!! I'm so happy to hear you're putting my formula to good use :) Thank you for sharing!!

Sprinkle Frosting: Easy, 5-Minute Recipe

Wednesday 7th of June 2023

[…] If you’re struggling to figure out how much buttercream you need for a larger cake, check out my buttercream calculator. […]


Sunday 7th of May 2023

Could you please make a chart for sheet cakes or would I just do one and a half batches of a square?


Monday 8th of May 2023

Hi Ashley,

I do need to make another chart for sheet cakes! I'm adding it to my to-do list, stay tuned!


Friday 5th of May 2023


Thank you for this I am not sure how to calculate how much buttercream to make if I have to decorate about 80 cupcakes with simple rosettes . Can you help me out?

Thank you


Monday 8th of May 2023

Hi Ghina,

It can vary a bit based on how big of a rosette you pipe, but I'd estimate that you'd need about 2 cups per dozen, so probably about 12-13 cups for 80 cupcakes. Hope that helps, happy baking!