How many times have you opened a baking recipe book and found the recipe you want to cook, to then open your cooking tin draw and discover you don’t have the right sized cooking tin? You have a round tin and the recipe demands a square tin. It seems to have to me all the time. I have to get out my high school level maths and figure out what tin I can use. This page is the answer to that problem. Just pop the tin dimensions specified by the recipe into one of the forms below and hey presto it will tell you what size of tin you can use instead.
Changing the tin shape shouldn’t affect the temperature at which you cook the cake. But it may take longer or shorter to cook. Square cakes tend to take longer to cook than round cakes. In square cakes the corners will cook more quickly than the middle so near the end of the cooking time – after about 80% of the time has passed, turn the cake around. Ideally don’t open the oven before then as this will impact on the temperature in the oven.

Brilliant, useful post. Definitely bookmarked. My sister moved house and passed on baking tins so this is extra useful for me. Thank you x
Hi Dawn,
Thanks for your comments. Just resurfacing after the birth. Glad this looks useful.
Thanks for reading.
Holly
Your square to round tin conversion does not work
Thanks for the help, really useful page
The round to rectangle – loaf shaped tin doesn’t work. It tells me I need to cook my cake for over 10 hours
My soo few recipe says to use 23cm round tin …. mine is 19cm…. is that a problem?
Amazingly useful, thank you sooooo much xx