Pan Size Converter
Converting 13x18 half-sheet pan to 9x13-inch pan? Find out exactly how to scale your recipe and adjust bake time.
Units
Recipe scaling
scale ingredients down × 0.5
Area ratio: 117 / 234 sq in
If you scale the recipe
Keep the original temperature and bake time
Area scaling keeps the batter depth similar. Start checking doneness about 5 minutes early.
If you keep the full batch
Split across two 9x13-inch pans
One target pan makes the full batch about 2× deeper. If using one pan, lower the oven by about 25°F (15°C) and allow extra center-bake time.
Popular conversions
13×18 half-sheet pan to 9×13 quarter-sheet pan: practical conversion
The target has 0.5× the base area of the original. Scale the ingredients by that amount to keep batter depth close to the original; the deeper-batter comparison below applies only when you keep the full batch.
| Original recipe | Target-pan amount | Practical handling |
|---|---|---|
| 200 g flour | 100 g | Weighing keeps the scaled amount precise. |
| 3 large eggs | About 1.5 eggs | Beat the eggs, then weigh about 75 g of beaten egg. |
| 1 cup liquid or sugar | 0.5 cups (about 1/2 cups) | Use a measuring cup for liquids; weigh dry ingredients where possible. |
If you keep the full batch: deeper batter
With the same 4 cups of batter, the layer is about 0.25 in (0.63 cm) deep in the 13×18 half-sheet pan, versus 0.49 in (1.25 cm) in the 9×13 quarter-sheet pan.
Bake-time starting point
For a scaled batch, keep the original temperature and time, then start checking about 5 minutes early. For a full batch in the target pan, plan on about 30–38 minutes for a brownie that takes about 20–25 minutes in the original half-sheet pan. Pan material, recipe density, and the intended texture can shift the final time.
What Matters for This Conversion
- - Quarter sheet is roughly half the area of a half sheet.
- - Scale ingredients down accordingly.
- - Bake dynamics differ because edges dominate smaller pans.
FAQ
Is quarter sheet half of half sheet?
In area terms, yes, approximately.
Do I just halve every ingredient?
Usually yes, then fine-tune seasonings and leavening if needed.
Will bake time halve too?
No. Time is not linear with quantity.
Do cookies behave differently?
Smaller trays can change airflow and spread.