It's important to note that this is length, not height. They are, of course, shorter than they are long.
If you're looking for their average height, it's much smaller, around 30-40 cm (12-16 inches) when they are lying down.
What is the height for a harp seal?
Harp seals are relatively small. They are about 1.5 to 1.8 meters (5 to 6 feet) long when fully grown.