Multiply miles by 1.609 to obtain the height in kilometers. For example, something 12 miles high would be approximately 19.31 kilometers high.
Multiply yards by 0.9144 to obtain the height in meters. For example, something 12 meters high would be 10.9728 meters high.
Multiply feet by 0.3048 to obtain the height in meters. For example, something 12 feet high would be 3.6576 meters high.
Multiply inches by 2.54 to obtain the height in centimeters. For example, something 12 inches high would 30.48 centimeters high. Multiply inches by 25.4 to obtain the height in millimeters. For example, something 12 inches high would be 304.8 millimeters high.