Pan Size Converter

Pan Size Conversion for Perfect Baking

Converting recipes between different pan sizes ensures your baked goods have the right depth and bake evenly. This calculator helps you adjust ingredient amounts when using a different pan size than the recipe calls for.

How Pan Size Conversion Works

The conversion is based on pan area:

Multiplier = New Pan Area ÷ Original Pan Area

New Amount = Original Amount × Multiplier

Common Pan Sizes and Areas

Square Pans

• 8×8 inch: 64 square inches (most common for brownies)
• 9×9 inch: 81 square inches
• 10×10 inch: 100 square inches

Rectangular Pans

• 9×13 inch: 117 square inches (most common for cakes, bars)
• 10×15 inch: 150 square inches
• 11×17 inch: 187 square inches (half sheet pan)

Round Pans

• 8 inch round: 50.3 square inches
• 9 inch round: 63.6 square inches (most common)
• 10 inch round: 78.5 square inches
• 12 inch round: 113.1 square inches

Common Conversions

9×13 to 8×8

• Multiplier: 0.55x (about half)
• 2 cups → 1.1 cups
• Use for: Halving a 9×13 recipe
• Baking time: Similar or slightly longer (deeper batter)

8×8 to 9×13

• Multiplier: 1.83x (almost double)
• 2 cups → 3.66 cups
• Use for: Doubling an 8×8 recipe
• Baking time: Similar or slightly shorter (shallower batter)

9×9 to 9×13

• Multiplier: 1.44x
• 2 cups → 2.88 cups
• Baking time: Slightly shorter

9 inch round to 8×8 square

• Multiplier: 0.79x
• Very similar areas, almost 1:1 conversion
• Baking time: Similar

Baking Time Adjustments

When Using Smaller Pan (More Depth)

• Batter is deeper, takes longer to bake
• Add 5-15 minutes to baking time
• Check doneness with toothpick
• May need to cover with foil if top browns too fast

When Using Larger Pan (Less Depth)

• Batter is shallower, bakes faster
• Reduce baking time by 5-15 minutes
• Check doneness earlier
• Watch for over-browning

Pan Depth Considerations

Pan depth affects baking:

• Standard depth: 2 inches (most common)
• Deep pans: 3+ inches (need longer baking time)
• Shallow pans: 1-1.5 inches (bake faster)

This calculator assumes standard 2-inch depth. Adjust time if your pan is significantly deeper or shallower.

Shape Considerations

Square vs Round

Square and round pans of similar area bake similarly:

• 8×8 square (64 sq in) ≈ 9 inch round (63.6 sq in)
• 9×9 square (81 sq in) ≈ 10 inch round (78.5 sq in)
• Corners of square pans may brown faster
• Round pans bake more evenly

Rectangular vs Square

Rectangular pans have more surface area:

• 9×13 (117 sq in) is 1.83x larger than 8×8 (64 sq in)
• More surface area = faster baking
• Shallower batter = shorter baking time

Step-by-Step Conversion Process

1. Identify pan sizes: Original and new pan dimensions
2. Calculate areas: Length × width for rectangles, π × radius² for rounds
3. Find multiplier: New area ÷ Original area
4. Scale ingredients: Multiply all ingredients by multiplier
5. Adjust baking time: Smaller pan = longer time, larger pan = shorter time
6. Check doneness: Use visual cues and toothpick test

Special Considerations

Layered Cakes

For layer cakes, consider:

• Round pans are standard for layer cakes
• 9 inch round is most common
• Converting to square works, but presentation differs
• Baking time may vary slightly

Brownies and Bars

For brownies and bar cookies:

• 8×8 and 9×13 are most common
• Depth matters - thicker brownies need longer baking
• Square pans create more corner pieces (some people prefer)

Sheet Cakes

For sheet cakes:

• 9×13 is standard
• 10×15 is larger party size
• 11×17 is half sheet pan size
• Shallow depth = faster baking

Tips for Successful Pan Conversions

1. Measure your pans: Don't assume - measure length, width, and depth
2. Calculate accurately: Use exact measurements for area calculations
3. Adjust time gradually: Start with estimated time, check early
4. Watch for doneness: Visual cues are more reliable than time
5. Consider depth: Deeper pans need longer baking
6. Test with toothpick: Clean toothpick = done
7. Rotate if needed: Larger pans may need rotation for even baking

Calculating Custom Pan Sizes

If your pan size isn't listed:

1. Measure dimensions: Length, width (or diameter for round)
2. Calculate area:
   • Rectangle: length × width
   • Round: π × (diameter/2)² = 3.14159 × radius²
3. Use area ratio: New area ÷ Original area = multiplier
4. Scale ingredients: Multiply by multiplier

Common Baking Pan Equivalents

• 8×8 square ≈ 9 inch round
• 9×9 square ≈ 10 inch round
• 9×13 rectangle ≈ 2 × 9 inch rounds
• 8×8 square ≈ 0.55 × 9×13 rectangle
• 9×13 rectangle ≈ 1.83 × 8×8 square