What this calculator does
Most Australian and British recipes give pan sizes in centimetres, while a lot of recipes, tins and cookbooks written for the US market use inches. Working out a 9x13 inch pan in cm, or any other pan size, is a plain length conversion: multiply each side by 2.54, the fixed number of centimetres in an inch.
The tricky part is not the maths but the pan itself. Pan sizes are usually measured across the top inside edge, not the outside of the tin, and manufacturers round to the nearest common size, so a "9 inch" tin might genuinely measure 22.5 to 23 centimetres depending on the maker. Treat the converted figure as the size to shop or bake by, not a precision engineering measurement.
The formula
Centimetres = inches × 2.54. Enter the pan's length and width in inches and both dimensions convert at once. The area in square centimetres is also shown, which is useful for scaling a recipe to a different sized tin while keeping the same batter depth.
| Term | Meaning |
|---|---|
| 2.54 | The exact, fixed number of centimetres in one inch, an internationally defined unit conversion. |
| Length and width | The two inside-edge measurements of a rectangular pan; for a round or square pan, enter the same value in both fields, or just the one dimension that matters. |
The inputs explained
| Field | What to enter |
|---|---|
| Pan length (in) | The pan's longer side, in inches. |
| Pan width (in) | The pan's shorter side, in inches. |
When to use it
Converting a US recipe
A recipe calling for a 9x13 inch pan can be matched to the nearest local tin once the centimetre equivalent is known, rather than guessing.
Buying bakeware
Shops in different countries list pan sizes in different units; converting first avoids ordering the wrong tin.
Scaling a recipe to a different tin
Comparing the area of two pan sizes in the same units shows roughly how much a batter needs to be scaled up or down, and whether the baking time will need adjusting.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
Pan length converted to centimetres, for a 9 inch wide pan
How the length side alone converts across a range of common pan lengths, with the width fixed at 9 inches so only one dimension changes at a time.
| Pan length (in) | Length in cm | Width in cm |
|---|---|---|
| 8 in | 20.3 cm | 22.9 cm |
| 9 in | 22.9 cm | 22.9 cm |
| 11 in | 27.9 cm | 22.9 cm |
| 13 in | 33.0 cm | 22.9 cm |
| 15 in | 38.1 cm | 22.9 cm |
Questions
What is a 9x13 inch pan in cm?
A 9x13 inch pan converts to 22.9 x 33.0 cm, using the fixed 2.54 cm/inch conversion factor. Manufacturers may round the actual tin slightly either way.
Should I measure the inside or outside of the pan?
Recipes and pan sizes are conventionally measured across the inside top edge, not the outer rim of the tin. Measuring the inside gives a more accurate match to what a recipe expects.
Does a bigger pan mean I should change the oven temperature?
Generally the temperature stays the same but the baking time changes: a wider, shallower pan with the same volume of batter usually bakes faster than a narrower, deeper one, so start checking a little earlier than the original recipe suggests.
Why do two "9 inch" tins from different brands seem to be slightly different sizes?
Pan sizes are rounded to common nominal figures by manufacturers, and small variations in wall thickness and measuring convention mean actual tins vary by a centimetre or so around the stated size. The conversion here is exact; the tin itself may not be.
For any other length conversion, see the general length converter. To scale a whole recipe up or down once the pan size is sorted, see the recipe scaler.