Convert a recipe to a different tin size
Convert a recipe between round, square, and rectangular tins, with every ingredient rescaled for you.
Free. No signup needed.The short answer
Scale by area, not by the number on the tin. An 8 inch (20cm) round to a 10 inch (25cm) is 1.56 times everything, not 1.25. Enter both tins below and every ingredient is rescaled for you.
Convert a recipe to a different tin size
BakerInbox
Swap the tin
Recipe is written for
You want to bake in
Multiply everything by
1.56x
The new tin holds 56% more batter
Your recipe, converted
Use
313g
Use
313g
Use
313g
Use
6whole
from 6.25, adjust liquid by feel
In the oven
More batter than the recipe was written for. Check about 10 minutes later than the original.
Scaling now follows batter volume, area and depth together, so a deeper or shallower tin is counted properly, not assumed the same. Round eggs to whole ones and adjust the liquid by feel. Raising agents scale, but past about double a batch it is safer to make two.
Keep your converted recipes with the orders they belong to, instead of on the back of an envelope.
Start free trialTin sizes and how they scale
| Round tin | Diameter (cm) | Area (sq in) | Scale from 8 in |
|---|---|---|---|
| 6 in | 15 | 28 | 0.56x |
| 7 in | 18 | 38 | 0.77x |
| 8 in | 20 | 50 | 1.00x |
| 9 in | 23 | 64 | 1.27x |
| 10 in | 25 | 79 | 1.56x |
| 12 in | 30 | 113 | 2.25x |
| 14 in | 36 | 154 | 3.06x |
Made with BakerInbox. Free cake tools at bakerinbox.com/tools
Converting tin sizes
Every tin conversion comes down to one number: how much bigger the new tin is by area. Multiply the whole recipe by it.
The maths
Scale by area, never by the number on the tin
Going from an 8 in round to a 10 in round is not a quarter more batter. Area grows with the square of the width, so it is 1.56 times as much. Scale by the tin number instead and you get a shallow, dry cake and no obvious reason why.
Shapes
A square tin holds more than a round one the same size
A 9 in square holds roughly what a 10 in round holds. If you are changing shape as well as size, the multiplier covers both at once, because it only ever compares the area of one tin with the area of the other.
In the oven
Same depth of batter, similar bake time
Keep the batter at the same depth and the oven does about the same work, so the timing barely moves. Check a bigger cake around ten minutes later than the recipe says, and a smaller one ten minutes earlier. Trust the skewer, not the clock.
Where it stops
Past double a batch, make two
Raising agents and eggs scale cleanly enough for a small jump. Much past double and the mixer struggles, the batter sits too long before it goes in, and the crumb suffers. Two batches side by side beat one heroic one.
FAQ
Common questions
How do I convert an 8 inch recipe to a 10 inch tin?
Multiply every ingredient by 1.56. A 200 g flour recipe becomes 312 g. Round eggs to the nearest whole one and adjust the liquid by feel.
What is a 9 inch round equivalent to in a square tin?
About an 8 in square. A square tin of the same measurement always holds more, roughly 27% more, because of the corners.
Do I change the oven temperature?
Not if the batter sits at the same depth. If it is noticeably deeper in the new tin, drop the oven by about 10C and give it longer, so the middle sets before the edges dry out.
Does this work for any recipe?
It works for batters and sponges. Enriched doughs and anything that depends on a set proving time need more care than a straight multiplier.
What size is a 20 cm cake tin in inches?
8 in. UK and European tins are sold in centimetres and the round numbers do not line up exactly: 20 cm is 7.9 in, and it is sold and used as an 8 in. The rest of the range: 15 cm is 6 in, 18 cm is 7 in, 23 cm is 9 in, 25 cm is 10 in, 30 cm is 12 in.
What is the square equivalent of a 20 cm round tin?
An 18 cm square. A square tin holds noticeably more than a round tin of the same width, because the corners add area, so going square means dropping about one size to keep the same amount of mixture. Swapping like for like leaves a square cake shallow and overbaked.
How do I measure a cake tin?
Across the base, not the top, and on the inside of the walls. Many tins slope outward, so measuring the rim can read a whole size larger than the tin actually bakes. Depth is measured inside too, from the base to the top edge.
Does this work as a cake pan converter?
Yes. A cake tin and a cake pan are the same thing, and the scaling is the same either way. Amounts can be entered in ounces, pounds or cups as well as grams, so a US recipe goes in as written and comes back in the unit you typed.
How do I convert a 9x13 pan to two 9 inch rounds?
A 9 by 13 inch pan holds about 117 square inches and a 9 inch round about 64, so two rounds come to 127. That is roughly 1.09 times the sheet, near enough to bake the same batter with no change. Enter both below to see it exactly.
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