Square Centimeters to Square Inches
Type a value in either box to convert between square centimeters and square inches. The factor is 0.155.
| Square Centimeters | Square Inches |
|---|---|
| 1 cm² | 0.155 in² |
| 2 cm² | 0.310001 in² |
| 3 cm² | 0.465001 in² |
| 5 cm² | 0.775002 in² |
| 10 cm² | 1.550003 in² |
| 25 cm² | 3.875008 in² |
| 50 cm² | 7.750016 in² |
| 100 cm² | 15.500031 in² |
How to use
- Enter a value in the Square Centimeters field.
- The Square Inches figure appears immediately — no button to press.
- Typing in the Square Inches field converts back to Square Centimeters the same way.
- Use the reference table for the values that come up most often.
Square Centimeters to Square Inches formula
To convert square centimeters to square inches, multiply by 0.15500031.
in² = cm² × 0.15500031
Why this factor: the square centimeter and the square inch are both defined against the square meter, so dividing one definition by the other gives 0.15500031 directly. Both definitions are set out in full below.
To go the other way, divide by 0.15500031 — or use the Square Inches to Square Centimeters converter, which is the same calculation reversed.
Worked example
Start with 50 cm². Multiply by 0.15500031 to get 7.750016 in².
50 cm² × 0.15500031 = 7.750016 in²
The converter above does this for any value you type, in either direction.
What is a square centimeter?
A square centimeter is the area of a one-centimeter square.
Definition: Exactly 1×10⁻⁴ square meter — because 0.01 m squared is 0.0001 m².
Where it is used: Small surface areas, contact and cross-sectional areas, and pressure calculations.
What is a square inch?
A square inch is the area of a one-inch square, used for small areas and pressure.
Definition: Exactly 0.00064516 square meter, following from the exact 25.4 mm inch.
Where it is used: Print and label areas, gasket and seal faces, and the denominator in psi.
Square Centimeters vs Square Inches
The square centimeter is a metric unit while the square inch is an imperial unit. That is why the factor between them is not a round number: the two systems were defined independently and only later tied together by exact agreement.
Frequently asked questions
How many square inches are in a square centimeter?
One square centimeter equals 0.15500031 square inches.
What is the formula to convert square centimeters to square inches?
Multiply the number of square centimeters by 0.15500031. To reverse it, divide by 0.15500031 instead.
How do I convert square inches back to square centimeters?
Divide by 0.15500031, which is the same as multiplying by 6.4516.
How many square inches are in 10 square centimeters?
10 cm² works out to 1.550003 in².
How is the square centimeter defined?
Exactly 1×10⁻⁴ square meter — because 0.01 m squared is 0.0001 m².