Square Cake Tin and Round Cake Tin Volume Comparison

The general rule to remember regarding comparing the volume of square cake tins to round cake tins is:

This rule assumes 2 things:

• Both tins have the same depth (height).
• Both tins are the same numerical size.

For example:

A 6 inch square cake tin holds 25%  (1/4) more than a 6 inch round cake tin.

A 10 inch square cake tin hold 25%  (1/4) more than a 10  inch round cake tin.

From a practical point of view, that’s all you need to know.

How the Rule is Calculated

For those who wish to know how the above rule is calculated, you will need to understand the following points.

1) Formula for volume of Square Cake Tin = length(l) x width(w) x depth(d).

Given the length and width of a square are the same, we can rewrite it as l² d

2) Formula for volume of Round Cake Tin = Pi(3.14) x radius squared (radius is half of the tins diameter) x depth(d).

We can write this as 3.14r²d

3) Remember, the rule requires both tins to have the same depth (height). So in the following examples, we will assume both tins have a depth of 4 inches.

Example 1:
Comparing 6 inch square cake tin to 6 inch round cake tin

6 inch Square Cake Tin volume = l² d = (6×6) x 4 = 144
6 inch Round Cake Tin= 3.14r²d = 3.14 x (3×3) x 4=113.04

Comparing the volume of the Square Cake Tin to Round Cake Tin:

144/113.04 = 1.2739  i.e. the volume of the Square Cake Tin is 1.2739 times greater than the Round Cake Tin. This is the same as 27.39% larger.

We can also confirm this using the percentage change formula = ((y2-y1) / y1)*100

Therefore: ((144-113.04) / 113.04)*100 = (30.96 / 113.04)*100 = (0.2739)*100 = 27.39% larger

Thus, 27.39% is simplified to being approximately 25%

Example 2:
Comparing 10 inch square cake tin to 10 inch round cake tin

10 inch Square Cake Tin volume = l² d = (10×10) x 4 = 400
10 inch Round Cake Tin volume = 3.14r²d = 3.14 x (5×5) x 4=314

Comparing the volume of the Square Cake Tin to Round Cake Tin:
400/314 = 1.2739  i.e. the volume of the Square Cake Tin is 1.2739 times greater than the Round Cake Tin. This is the same as 27.39% larger.

We can also confirm this using the percentage change formula = ((y2-y1) / y1)*100

Therefore: ((400-314) / 314)*100 = (86 / 314)*100 = (0.2739)*100 = 27.39% larger

Thus, 27.39% is simplified to being approximately 25%

Summary

As a rough but useful guide, remember that: