Here is a flowchart to input the side of a square and calculate its perimeter if the side is greater than 10:

START ├─ Input side of the square (side) ├─ IF side > 10 THEN │ ├─ Calculate perimeter = 4 * side │ ├─ Display perimeter ├─ ELSE │ ├─ Display "Side is not greater than 10" └─ END

Note: The flowchart assumes that the input for the side is a valid numerical value.