Two 9-inch Rounds to 9×13 Rectangle:
The Nearly Perfect Match
Two layers
16 cups total
Single layer
14.6 cups
Use 92% of ingredients - almost the same!
✨ This is one of the easiest conversions!
The volumes are so close, you could even use 100% and just have a slightly taller cake
Why This Conversion Is Nearly Perfect
The Math Is Beautiful
Depth Comparison
Each 9" layer:
Usually 1.5-2" deep
9×13" result:
About 2" deep
✓ Almost identical depth!
Minimal Adjustments Needed
Same Temp
Keep at 350°F - no adjustment needed for this conversion
+5-10 Minutes
Single thick layer takes slightly longer than two thin ones
Watch Corners
Rectangle corners cook faster than round edges
Pan Converter
Pro Baker's Secret
"When converting from two 9-inch rounds to 9×13, I often just use the full recipe (100% instead of 92%). The extra 8% gives you a slightly taller cake that's perfect for sheet cakes. No one ever complains about a too-tall cake!"
The 100% Method:
- • Use all the batter from the layer recipe
- • Fill pan about 2/3 full (perfect!)
- • Add 8-12 minutes to baking time
- • Get a bakery-style tall sheet cake
Quick Conversion Examples
If Using 92% Scaling:
Or Just Use 100%:
Honestly? The 8% difference is so small, most bakers just use the full recipe:
- ✓ No math needed
- ✓ Slightly taller cake
- ✓ More impressive presentation
- ✓ Extra batter? Make a cupcake!
When to Use This Conversion
✅ Perfect For:
- • Potlucks (easier transport)
- • Picnics (no stacking issues)
- • Kids' parties (easy squares)
- • Freezing (flat storage)
- • When you have one 9×13 pan
💡 Consider:
- • Less frosting surface than layers
- • No middle layer of filling
- • Different presentation style
- • May need moisture boost
- • Corners vs. round edges