Kaynat Enterprises

A standard boxing ring is a square platform, typically between 16 and 24 feet (4.9 to 7.3 meters) inside the ropes. The ropes are held up by corner posts and are typically about 1 inch in diameter. The ring floor is padded and covered with canvas. 
Here's a more detailed breakdown: 

Overall Size:The overall size of the ring, including the apron (the area outside the ropes), can vary, but the inner space within the ropes is usually 16 to 24 feet square.

Ropes:There are typically four ropes, spaced at heights of approximately 18, 30, 42, and 54 inches (46, 76, 107, and 137 centimeters) above the mat.

Platform:The platform is raised from the ground, usually 3 to 4 feet (0.91 to 1.22 meters), and covered with padding and canvas.

Padding:The padding on the floor is typically about 1 inch (25mm) thick.

This video explains the dimensions of a professional boxing ring:A standard boxing ring is a square platform, typically between 16 and 24 feet (4.9 to 7.3 meters) inside the ropes. The ropes are held up by corner posts and are typically about 1 inch in diameter. The ring floor is padded and covered with canvas. This video explains how to measure a boxing ring for the canvas: