The perfect birthday needs the perfect birthday cake. One that tastes delicious and is just the right size to feed all of your guests.
This vanilla cake calculator will give you the ingredients you need for any size of cake tin as well as the answers to lots of other FAQs to help you get your cake just right.
One post on my blog that’s always popular is my all-in-one vanilla sponge birthday cake. It’s the recipe I use for almost all of my family’s birthday cakes and I absolutely love the idea that people are making and enjoying this on their family birthdays too.
However, it seems that popularity comes with lots of questions and I’m finding similar ones coming up again and again. People have told me that they’ve been scrolling through the comments to see if I’ve answered the questions before but with over 125 comments and counting it cannot be easy to spot the answer you’re looking for in amongst everything else.
To try and help you all out I thought I’d pull together a quick post to answer all of your birthday cake FAQs as best I can and of course if I find new questions popping up in future I’ll add them in here.
Frequently Asked Questions
What ingredients do I need to make this cake in a different size?
What temperature should I bake the cake at?
How long should I bake my cake for
Can I bake two layers in one deep tin?
Can this recipe be used to make cupcakes?
Can this cake be used to make tiers?
How far in advance can you make the cake?
Can you freeze the cake?
Can I use butter instead of margarine?
Can I substitute plain flour for self-raising flour?
What size eggs should I use?
Can I make this cake gluten-free?
How much fondant do I need to cover my cake?
What ingredients do I need to make this cake in a different size?
The most comment question I’m asked is how to calculate the quantities to make the cake in a different size. To help you I’ve built this handy little calculator (I’m quite proud of myself for getting this working actually 🙂 ).
All you need to do is pop your tin size and the number of layers of sponge you want in your cake into the green boxes and it’ll tell you what you need. The first calculator is for a round tin and the second is for a square or rectangular tin.
I’ve also calculated the ingredients needed to coat the cake in a layer of buttercream (with buttercream in between the layers too).
You need to enter the tin size in centimetres, if you only know yours in inches, simply multiply it by 2.5.
NOTE – I’ve not tested the cake in all possible sizes (I don’t have all those different tins for a start) so cannot guarantee success, However, as long as you don’t stray too far away from the original size I expect it should still work well.
Round Cake
- 0 g self-raising flour
- 0 tsp baking powder
- 0 egg(s)
- 0 g soft margarine or butter
- 0 g caster sugar
- 0 drops vanilla extract
- 0 tsp milk
- 0 g butter
- 0 g icing sugar
- 0 tsp vanilla extract Approx.
- 0 tsp milk
Square or Rectangular Cake
- 0 g self-raising flour
- 0 tsp baking powder
- 0 egg(s)
- 0 g soft margarine or butter
- 0 g caster sugar
- 0 drops vanilla extract
- 0 tsp milk
- 0 g butter
- 0 g icing sugar
- 0 tsp vanilla extract Approx.
- 0 tsp milk
What temperature should I bake the cake at?
You can bake this vanilla cake at the same temperature specified in the original recipe regardless of the size of tin you're using.
How long should I bake my cake for?
As long as you split the mixture into sandwich tins the cooking time will be the same as for the original recipe.
Can I bake two layers in one deep tin?
Yes you can. However it will take longer to bake.
If you put the mixture for two layers into now deep tin you'll need to bake the cake for 45-50 minutes.
Can this recipe be used to make cupcakes?
Yes, you can find the recipe to make this cake as cupcakes here.
Can this cake be used to make tiers?
My parties are all pretty small so I've never needed a cake big enough to justify tiers. It is quite a soft, light sponge and so I would expect it to be fine for 2 tiers but personally I wouldn't risk 3.
If you are planning on making two tiers remember to include some sort of support in the lower layer (strong straws or dowelling cut to the height of the cake, and also put the top tier onto a thin cake board the same size as the cake (this adds additional support and also stops the moisture from the sponge ruining the fondant on the bottom layer).
How far in advance can you make the cake?
I usually bake my cakes on a Thursday and decorate them on a Friday for a Saturday party. We only have small parties so there's usually some leftovers which have always lasted for a few days after the party.
Make sure you store it in an airtight container to keep it fresh and if the weather is particularly warm I'd suggest keeping it in the fridge.
Can you freeze the cake?
Yes, you can freeze the undecorated sponge. Simply wrap it in clingfilm or an airtight bag and pop it into the freezer. When you want to use it remove it from the freezer and then make sure it's fully defrosted before decorating.
Can I use butter instead of margarine?
Yes, just make sure you take the butter out of the fridge a little before you want to start baking to allow it to soften.
Can I substitute plain flour for self-raising flour?
I've only ever used self-raising (as I've always got it in the cupboard). Nigella suggests you can substitute plain flour by simply adding an extra 2 tsp of baking powder for each 150g of flour used (so for my original recipe you'd need an additional 3 tsp of baking powder).
What size eggs should I use?
I use whatever I have in the fridge! Most of the time that'll be medium eggs but it works just as well using large.
Can I make this cake gluten-free?
You should be fine to substitute the self-raising flour for a gluten-free self-raising flour. Also, double check that the brand of baking powder you're using doesn't contain gluten (some do, some don't).
How much fondant do I need to cover my cake
If you'd like an idea of how much fondant you need to cover your cake then head on over to my fondant calculator where it'll tell you for any size of round, square or rectangular cake.
FREE GRAMS TO CUPS CONVERSION CHARTS
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This post was originally published on 17th May 2016 and updated with an improved calculator and more FAQs on 11th July 2018.
Rebecca says
I’d like to make a watermelon style cake for my daughter – needs 3 x 9 inch cakes plus a dome.
I notice you say you don’t think your basic sponge would be good for more than 2 tiers…. help!!! What recipe would, or what do I look out for?
I’d really like to give it a go as she’s watermelon mad!
Charlotte Oates says
It should be OK for that amount of cake.
Rebecca says
Thank you very much!
Narinder Saggu says
Cakes look fabulous
Narinder Saggu says
Hi Charlotte! I was searching best birthday spong cake and your website has got me hooked. I need to make a birthday cake sponge for my son and have a rectangle tin 10 inch by 8 inch and it 2 inch deep.
What is the mixture measurement please?
Also can i cut this sponge in half and buttercream it?
I will be using a cake topper, will this rise quiet big?
Thanking you
Mrs S
Charlotte Oates says
For a tin that depth you’d need to put 25cm x 20cm with 1 layer into my calculator (it’ll have 3 eggs). A tin of that depth is only suitable to make 1 layer and it would be too thin to slice in half. If you’d like a taller cake then you’ll need to bake two separate sponges.
katy says
hi Charotte the calculator wont load and i have a 18cm by 4 cm tin
and a 23 by 6 cm tin how much mixture would i need?
Charlotte Oates says
Hi Katy, are they round or square. Your tins are different depths, do you want that large cake to be deeper than the smaller one or the same depth?
Kath says
My cakes are in the oven- and overflowing the tins! I measured them and they are definitely 20cm. Help please!
Charlotte Oates says
What depth are the tins you’re using? I’ve made this cake again and again and never had that problem.
Krystyna says
Thanks Charlotte, that’s the 2nd year in row that your birthday cake calculator has saved my birthday cake bacon.
I did it again, I made a recipe from the BBC website, it all went wrong and then I did your all-in-one recipe and used your calculator and ‘bingo’ perfect cake.
Next year, I will come here first.
lucy says
Hi Charlotte, wow what a popular recipe! Could you please give me the quantities for a 12 inch square cake tin 4 inches deep? Would it be best to divide the quantity by 2 and cook 2 separate layers or just do the whole quantity in one cake and cut when baked? Also how long to cook for please?
Charlotte Oates says
Personally I always split the mixture into two tins and cake them separately. However, I’ve known lots of people to use one deep tin instead. If you split the mixture it’ll take the same amount if time as in the original recipe. If you want to use a deep tin leave it in the over for 45 minutes before checking it.
The quantities you need are…
620g flour
620g sugar
620g margarine
11 eggs
5.5 tsp baking powder
1/2 tsp vanilla extract
5.5 tsp milk
Hannah says
Hello I have used the recipe for 8″ tins and have loved the results.
The calculator is a great tool. Thank you.
Would this recipe work for a giant cupcake? If so any idea of ingredients quantities? I’m really struggling to master giant cupcakes, but love the look of them.
Also if I’m adding food colouring (gel) to the sponge, should I use less of any ingredient?
Thanks in advance x
Charlotte Oates says
I’ve not tried it as a giant cupcake. It should work although as a giant cupcake is deeper it will need to be cooked for longer (it depends on the depth of the cake as to how much longer). As long as you stick to gel colours (rather than the liquid ones) you won’t need to change the other ingredients.
Stacey says
Hello. Im baking in tins im now familiar with. They are 15cm×8cm and 23×9 so quite deep. Whats thw best recipe for these sized of cakes?
Charlotte Oates says
Hi Stacy. If you’re using deep tins you can put 2 layers of mixture into each tin. As the cakes are deeper they’ll take longer to cook so don’t check them until they’ve been in the over for 45 minutes.
Pam says
Hi Charlotte, a few weeks ago I asked about making a sponge cake for about 40 people I followed your advice and the cake worked out perfectly !! I had so many lovely comments on how lovely and light it the sponge was, people came back for seconds and even thirds!!, I won’t be using any other recipe from now on -so thank you very much. Don’t suppose you have a brilliant carrot cake recipe too?!!
Charlotte Oates says
That’s fantastic, I’m so glad everyone enjoyed it x
Hannah says
If I wanted lemon flavouring in my cake, would I substitute the milk for lemon juice and miss out the vanilla?
Charlotte Oates says
I’d add some finely grated lemon zest of switch the vanilla extract for lemon extract.
Bina says
Hi I’m planning to make my daughter a Elsa doll cake for her 3rd birthday. So need a tall cake that doll can fit into up to her hips.
I have 1 21cm and 3 inches deep cake tin. If I made this cake in 1 tin but did it 4 times then butter creamed them together would it; 1 hold?
2 easy to shape?
Also as wanting hight for my cake, can I put mixture for x 2 21cm sandwich tins into my 1 tin? And how long would I bake for? And at what temperature in my fan over?
Charlotte Oates says
Hi Bina, When you say you want 4 layers, do you want 4 layers 3″ deep or if you used the deep tin would you only make 2 and split them in half?
Rebecca Dedman says
Please can you tell me the quantity of ingredients needed for a round 2 tier cake made in 2 x 10 inch (25cm) round sandwich tins? Each sandwich tin is 2.5 inches deep.
Charlotte Oates says
Hi Rebecca, I’d recommend using the calculator for a 25cm round tin with 4 layers to give the quantities you need. As the tins are deeper you’ll need to bake the cakes for longer. I’d suggest waiting until they’ve been in the oven for 45 minutes before checking.
Pam says
Hi I need to make a rectangular sponge cake enough for 40 people – could you please advise what size tin would be appropriate? I love the all in one method, works perfectly every time. Many thanks
Charlotte Oates says
Hi Pam, I’ve not used this recipe to make a cake that large before but it should be OK. I’d suggest having a look at what large cake tins are available and then popping the dimensions into my calculator to see which gives you the right amount. As a guide I’d say you’d want to have at least 14 eggs in your mixture so for example 2 layers of 40-28cm should be large enough.
Pam says
Hi Oh trust me to be different ;-). Thanks for the advice. Will give it a go.
Laura says
Hi, I made the cake and it turned out great but was just a little on the dry side. would you suggest I add more milk?
Charlotte Oates says
I don’t think that would solve the problem. I’d suggest checking it a little earlier as dryness could be an indication it stayed in the oven a little longer than needed (this is quite possible as ovens can vary a little in temperature).
catherine says
Hi Charlotte,
Can i use unsalted butter instead?
thanks a mill xx
Charlotte Oates says
You can, it’ll just have a slightly different flavour.
Lynne says
Thank you so much for this delicious recipe. I made four layers for the cake I made and it was absolutely fine, no problems at all. I’ve already passed on the recipe.
Charlotte Oates says
4 layers, that must have been huge! I’m glad it worked well for you x
Lisa says
What measurements did you use for a layer? I’m looking at doing this today x
Charlotte Oates says
A single layer is made in a 2.5cm deep tin
Isabel says
Hi Charlotte,
I am making a cake for twenty people in a 9” tin. What quantities do you suggest I use so that i have enough cake? Thank you 🙂
Charlotte Oates says
To feed 20 people with a 9″ cake I’d suggest making it 3 layers deep rather then two that way people get a smaller but deeper slice. If you want to do that the use twice the ingredients listed in the recipe and split it between 3 9″ tins.
mrs hussain says
thank you. I will tell you how the cake turn out
mrs hussain says
Hi im planning to bake a cake size is 12inch x 8inch and its 3inch deep. What do you mean by layer?? I wanted to bake one cake and cut in half and fill with jam and white chocolate buttercream so this is the right amount
Number of layers 2
BIRTHDAY CAKE SPONGE
450g self-raising flour
450g soft margarine
450g caster sugar
8 egg(s)
4 tsp baking powder
12 drops vanilla extract
4 tsp milk
BUTTERCREAM
440g butter
880g icing sugar
1 tsp vanilla extract
5.5 tsp (approx.) milk
Or this amount
Number of layers 1
BIRTHDAY CAKE SPONGE
225g self-raising flour
225g soft margarine
225g caster sugar
4 egg(s)
2 tsp baking powder
6 drops vanilla extract
2 tsp milk
BUTTERCREAM
220g butter
440g icing sugar
0.5 tsp vanilla extract
2.5 tsp (approx.) milk
Can I use butter not margarine. And can you also tell the amount for white chocolate buttercream for this cake size that will cover all.
Charlotte Oates says
You can use butter for the cake instead of margarine, just make sure it’s at room temperature.