To calculate the perimeter of a square, you can use the formula:
\[ \text{Perimeter} = 4 \times \text{side length} \]
Given that the side length of the square is 7 cm, the calculation is as follows:
\[ \text{Perimeter} = 4 \times 7 , \text{cm} = 28 , \text{cm} \]
Therefore, the perimeter of the square is 28 cm.