Cake Weight to Size: What a 1 lb Cake Looks Like

Updated September 2026 · Baking Resources

A 1 lb cake is a 6 inch round. A 2 lb cake is an 8 inch round. A 3 lb cake is a 9 inch, a 4 lb cake is a 10 inch, and a 5 lb cake is an 11 or 12 inch. Those weights are the finished cake with its frosting on, which is how bakeries that sell by weight actually weigh them.

Cake weight to size is not a fixed conversion, though, and that is the part nobody tells you. The same 8 inch pan can produce a 2 lb cake or a 5 lb one depending on how tall the layers are and how heavy the batter is. The chart below gives the common answers, and then the arithmetic so you can work out any cake you like.

Working backward from a headcount instead? Our free cake servings calculator takes a pan size and shows you the cut grid, so you can see the pieces before you commit to a size.

Updated September 2026

Cake weight to size at a glance

This is the chart for cakes sold by weight: a light sponge, torted, with a cream or light buttercream coat. It is the most common style behind a "1 kg cake" or a "2 lb cake."

A square holds more cake than a round of the same nominal number, which is why the square column runs an inch smaller for the same weight. An 8 x 8 square has 64 square inches of floor and an 8 inch round has 50.3, so the square is 27 percent bigger even though they share a name.

The math behind cake weight to size

Two numbers run the whole thing.

Batter weighs about 240 g per cup. That is the same as milk on our ingredient weights chart, which makes sense: a cake batter is mostly water, sugar and flour with some fat and a little beaten-in air.

A cake loses about 10 percent of its weight in the oven, as steam. It goes in at 240 g per cup of batter and comes out at roughly 216 g.

Put those together and you get the rule worth remembering:

2 cups of batter bakes into about 1 pound of cake.

Everything else on this page is that rule with a pan size attached. If you want the finished weight of any cake, work out the batter volume, multiply by 216 g, and add the frosting.

Batter is not all the same weight

The 240 g figure is a middle number, and the spread is wide enough to matter on a big cake. Weigh your own once and write it on the recipe.

That is a 40 percent spread from top to bottom. A 9 inch pan filled with pound cake batter finishes noticeably heavier than the same pan filled with sponge, and neither one is wrong.

Measuring it takes 20 seconds. Set a 1 cup measure on the scale, tare to zero, spoon in batter and level it off. The number you get is your batter density, and it does not change much between batches of the same recipe.

What each pan weighs when you bake it

These are bare cakes, no frosting, using a standard 240 g per cup batter and filling every pan to the two-thirds line. Capacities match our cake pan converter, so nothing here can disagree with the tool.

That cupcake row is the sanity check. Weigh an unfrosted cupcake and you will get somewhere in the 55 to 65 g range, which tells you the whole model holds together.

Notice the gap between this table and the ordering chart at the top. A 6 inch pan filled properly gives 1 lb 4 oz of bare cake, yet a 6 inch cake is sold as 1 lb. Both are true. Cakes sold by weight are usually baked as one shallower sponge and then split, so there is less cake in them than a full 2 inch pan holds. Our round cake pan sizes guide has the layer heights side by side.

How much weight the frosting adds

Frosting is heavier than people expect. American buttercream weighs about 247 g per cup, which is heavier than the cake it sits on, and a fully frosted cake can be a third frosting by weight.

Whipped cream is much lighter, around 129 g per cup, which is exactly why cream-frosted cakes weigh less at the same diameter. That difference alone is about 500 g on a 9 inch cake.

Our frosting calculator splits the total into crumb coat, filling, outside coat and piping, and the piping line is where the weight really climbs. If you want to see the amounts by frosting type, that is the place.

Worked example: what a 2 lb cake really contains

Someone asks for a 2 lb cake. Here is the build, start to finish.

Step 1. Set the target. 2 lb is 907 g of finished, frosted cake.

Step 2. Decide the coating. A light whipped cream finish on an 8 inch cake takes about 2 cups, at 129 g per cup, so 258 g of cream.

Step 3. Subtract it. 907 minus 258 leaves 649 g of baked cake.

Step 4. Work back to batter. 649 divided by 216 g per cup gives 3 cups of batter.

Step 5. Check the pan. Three cups in an 8 inch round is 3 x 14.44 = 43.3 cubic inches, spread over 50.3 square inches of floor. That is 0.86 inches of batter, which bakes into a sponge roughly 1 1/3 inches tall.

Step 6. Sanity check the result. One 1 1/3 inch sponge, split horizontally into two thin layers, cream between them and cream outside. That is exactly what a 2 lb cake looks like when you cut into it, and it is why they feel light for their size.

Swap the cream for American buttercream and the same 8 inch cake jumps: 3 cups of buttercream at 247 g adds 741 g, so the same sponge finishes at nearly 3 lb.

A second example: an American layer cake

Now the other extreme. Two full 9 inch layers, filled and frosted with American buttercream.

That is 7 1/2 lb, on a cake nobody would call big. It is the same 9 inch diameter as the 3 lb cake in the ordering chart, and it weighs two and a half times as much. Height and frosting choice, not diameter, are doing all the work.

This is the single most useful thing to understand about cake weight to size. Diameter tells you how wide the top is. Weight tells you how much cake there is. They only line up when everyone agrees on the height.

Turning weight into servings

Weight is actually a better guide to headcount than diameter, because it accounts for height.

• A generous party slice is about 5 oz, or 140 g, of finished cake.
• A small slice, the kind you cut when everyone has already eaten, is about 2 1/2 oz, or 70 g.
• A formal 1 x 2 inch wedding piece is smaller still, and the count for those comes out of geometry rather than weight.

For the formal counts, use the cake servings calculator, which draws the cut grid. A 9 inch round is 12 party servings or 32 wedding servings, and both numbers are honest. They are different piece sizes, not different cakes.

Why two cakes the same size weigh different amounts

Five things move the number, in rough order of how much they matter:

1. Layer height. Doubling the batter in a pan doubles the cake weight. This is the biggest lever by a wide margin.
2. Frosting type. Buttercream is nearly twice the weight of whipped cream per cup. Fondant over buttercream adds more again, and the fondant weight by pan size chart has the figures.
3. Batter density. Foam sponge to pound cake is a 40 percent spread, as the table above shows.
4. Bake time. A cake baked 10 minutes long loses more water and finishes lighter and drier. Weight loss and dryness are the same event.
5. Fillings. Fruit, jam, curd and mousse layers add weight without adding any height to speak of.

That last one catches people. A jam filling can add 200 g to an 8 inch cake and change nothing you can see from the outside.

How to weigh a cake properly

If you need an accurate finished weight, weigh in stages rather than at the end.

1. Weigh the empty pan. Write it down.
2. Weigh the filled pan before it goes in the oven. Subtract, and you have the batter weight.
3. Weigh the cooled cake once it is out of the pan. Subtract from the batter weight and you have your actual bake loss, usually 8 to 12 percent.
4. Weigh the frosting bowl before and after coating. The difference is what went on the cake.
5. Add the last two numbers for the finished weight.

Do this once with a recipe you make often and you will never have to guess again. It also tells you whether your oven runs hot: a bake loss over 13 percent usually means the temperature is high or the cake stayed in too long, which is the same problem behind dry muffins.

A note on cake boards and boxes: they are not cake. A sturdy 10 inch board plus a box can add 200 to 300 g, so weigh the cake on its own if the number matters.

FAQ

How big is a 1 lb cake?

A 6 inch round, roughly 2 to 3 inches tall once it is layered and coated. It gives 3 or 4 generous slices, or 6 smaller ones. In square terms it is about a 5 x 5.

What size is a 1 kg cake?

An 8 inch round, the same as a 2.2 lb cake. It feeds around 7 people generously or 14 in smaller pieces, and it is usually one sponge split into two thin layers with cream between them.

How much does a 9 inch two-layer cake weigh?

Anywhere from about 4 1/2 lb to 7 1/2 lb. Thin box-style layers with a normal coat of buttercream land near the bottom of that range, and full 2 inch pans with heavy frosting land near the top.

How many cups of batter make a pound of cake?

Two cups, near enough. A cup of standard batter is about 240 g and loses roughly 10 percent of that in the oven, leaving 216 g of cake, so two cups gives 432 g against a pound's 454 g.

Does frosting count in the weight of a cake sold by weight?

Usually yes. Shops that sell by weight almost always weigh the finished, decorated cake, which is why a 2 lb cake contains well under 2 lb of actual sponge. If it matters for a special order, ask.

Why does my cake weigh less than the batter I poured in?

Water left as steam, which is what baking is. Expect to lose 8 to 12 percent of the batter weight. A big loss means a long or hot bake, and a very small loss can mean the middle is still underbaked.

Is a square cake heavier than a round of the same size?

Yes, by about 27 percent at the same nominal size and height. An 8 x 8 square has 64 square inches of floor against an 8 inch round's 50.3. That is why serving charts put squares a size below rounds for the same headcount.

How do I scale a recipe up to hit a target weight?

Work out the batter volume you need, divide by the volume your recipe currently makes, and multiply everything by that factor. The recipe scaler handles the fractions, and our guide on how to scale a recipe covers the ingredients that do not scale in a straight line.