How to Measure Pizza Size Accurately

Did you know that when pizzerias advertise a “12-inch pizza”, they are referring to the diameter of the raw dough pan, not necessarily the cooked pizza? Cooked dough shrinks in the oven!

Here is how to properly measure pizza size and calculate its true surface area.

---

Step 1: Measure the Diameter

1. Place a ruler or tape measure straight across the center of the pizza.
2. Measure from outer crust edge to outer crust edge through the absolute center point.
3. Record the measurement in inches or centimeters (e.g., $d = 12\text{ inches}$).

---

Step 2: Calculate the Radius

The radius ($r$) is half of the diameter ($d$): $$r = \frac{d}{2}$$

For a 12-inch pizza: $$r = \frac{12}{2} = 6\text{ inches}$$

---

Step 3: Calculate the Surface Area

Use the area formula for a circle: $$\text{Area} = \pi \times r^2$$

Where $\pi \approx 3.14159$.

For a 12-inch pizza: $$\text{Area} = 3.14159 \times 6^2 = 3.14159 \times 36 = 113.1\text{ square inches}$$

---

Why Diameter Measurements Are Deceptive

If a 12-inch pizza shrinks by just 1 inch in the oven to 11 inches:

• 12″ Area = 113.1 sq in
• 11″ Area = 95.0 sq in

That 1-inch loss in diameter equals a 16% loss in total pizza!

Use our free Pizza Size Calculator to measure and compare any pizza sizes in seconds.