Cake Tin Size Converter
Right recipe, wrong tin
If a recipe was written for a 20 cm round tin and you only own a 23 cm one, the batter will be too shallow and bake wrongly unless you scale it up. The honest way to do this is by area, not by diameter, because area is what determines how much mixture the tin holds. This tool works out the area of both tins, including the difference between round and square, and tells you the single number to multiply every ingredient by.
A square tin holds noticeably more than a round tin of the same width, which surprises people. Keep the oven temperature the same when you scale, and just adjust the bake time: a shallower, wider cake cooks a touch faster, a deeper one slower.
Frequently asked questions
Is the cake tin size converter converter free?
Yes. It is completely free, with no sign-up and nothing to install. It runs entirely in your browser.
Are these figures exact?
They are reliable guides based on standard UK values, but ingredients, ovens and appliances vary. For anything involving meat, always check it is cooked through with a thermometer rather than relying on time alone.