Convert 9-inch Square to 9-inch Round Pan

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Common Baking Conversions

Weight

  • 1 cup all-purpose flour ≈ 125g
  • 1 cup granulated sugar ≈ 200g
  • 1 cup brown sugar ≈ 220g
  • 1 stick butter = 113g
  • 1 large egg ≈ 50g

Volume

  • 1 cup = 237ml = 16 tbsp
  • 1 tbsp = 3 tsp = 15ml
  • 1 fl oz = 30ml = 2 tbsp
  • 1 liter = 4.23 cups
  • 1 gallon = 3.785 liters

Temperature

  • 350°F = 175°C = Gas Mark 4
  • 375°F = 190°C = Gas Mark 5
  • 400°F = 200°C = Gas Mark 6
  • 425°F = 220°C = Gas Mark 7
  • 450°F = 230°C = Gas Mark 8

Pro tip: For accuracy in baking, always prefer weight measurements (grams) over volume measurements (cups).

⚠️ The 9-inch Trap: Don't Use All Your Batter!

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9×9 Square

10 cups

81 square inches

⭕

9" Round

8 cups

63.6 square inches

Only use 78% (multiply by 0.78)

The remaining 22% = perfect for 2-3 bonus cupcakes!

Why Same "9-inch" Creates Different Volumes

The Geometry Truth

  • • Square: 9 × 9 = 81 square inches
  • • Round: π × 4.5² = 63.6 square inches
  • • Difference: 27% less capacity

Visual Comparison

Imagine cutting the corners off your square pan - that's exactly the volume you lose when switching to round. Those four corners represent 2 cups of capacity!

Quick Conversion Guide

Square Recipe ×0.78 Round Pan Extra Batter Use
3 cups flour → 2⅓ cups ⅔ cup for cupcakes
4 eggs → 3 eggs 1 egg for glaze
2 cups sugar → 1½ cups + 2 tbsp Save for topping
1 cup butter → ¾ cup + 1 tbsp Perfect!

Baking Adjustments for Round Pans

🌡️ Temperature

No change needed. Keep at original temperature. Round pans distribute heat evenly.

⏱️ Time

Add 3-5 minutes. Slightly deeper batter in center needs extra time. Start checking at original time.

📏 Even Baking

Better results! No corners means more uniform browning and texture.

Already Mixed Your Batter?

Three Smart Solutions:

Option 1: Cupcake Bonus

Fill round pan 2/3 full. Use extra for 2-3 cupcakes. Bake cupcakes at same temp for 18-20 minutes.

Option 2: Tomorrow's Treat

Store extra batter in fridge (up to 24 hours). Perfect for pancakes or muffins tomorrow!

Option 3: Mini Layer

Have a 4-inch or 6-inch pan? Make a mini version for taste-testing or gifting.

Pro Baker's Secret

"When I convert from square to round, I actually prefer it! The round shape eliminates dry corners, and the slightly thicker center creates a moister crumb. Plus, those 'extra' cupcakes? They're perfect for testing if the cake is good before serving to guests!"

— Sarah Chen, Professional Pastry Chef

Related Conversions:

Reverse Conversion:
Similar Conversions:

Common Baking Problems & Solutions

Batter overflowing in oven!

Diagnosis:

Used 100% of square recipe in smaller round pan. The 27% volume difference caused overflow.

Solution:

Immediately: 1) Lower temp by 25°F, 2) Place sheet pan below to catch drips, 3) Open oven briefly to scoop excess. Next time: Use only 78% of ingredients or choose our for same volume.

Cake sunk in the middle

Diagnosis:

Overfilled round pan disrupted proper heat circulation. Round pans need center space for even baking.

Solution:

Never fill pans more than 2/3 full. For this conversion, that means using exactly 78% of the square recipe. The math matters!

Don't have measuring cups for 78%

Diagnosis:

Calculating 78% of measurements like '2/3 cup' can be tricky without proper tools.

Solution:

Use our Baker's Percentage Calculator or this trick: Make full recipe, weigh total batter, use 78% by weight. Much more accurate!

Frequently Asked Questions

Why does 9-inch square hold more than 9-inch round?

The "9 inches" measures different things! Square: 9×9 = 81 square inches of area. Round: π×4.5² = only 63.6 square inches. Those corners in the square add 27% more space. Think of it this way: if you cut the corners off your square to make it round, you'd lose over 2 cups of capacity!

Can I just use a deeper round pan instead?

Yes! A 9×3 inch round pan (instead of standard 9×2) gives you 12 cups capacity - even more than the square. This is perfect if you want to keep the full recipe. Find deep pans at restaurant supply stores. Just add 5-10 minutes to baking time for the extra depth.

What if my recipe specifically needs corner pieces?

Some recipes (like brownies with crispy edges) rely on corners. For these, stick with square pans or try our reverse conversion. Round pans eliminate corners completely, which changes texture distribution.

Is the 0.78 conversion exact or approximate?

It's mathematically exact: 63.6 ÷ 81 = 0.785, rounded to 0.78 for practical use. For most recipes, this precision is perfect. For finicky recipes like soufflés or angel food cakes, weigh your batter and use exactly 78.5% for best results.

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