What is 21 inches to centimeters? The answer is that 21 inches equals 53.34 centimeters.
How to convert 21 inches to cm? We know that one inch is equal to 2.54 centimeters, so to convert 21 inches to centimeters, we must multiply the amount of centimeters by 2.54, which means that 21 inches is equal to 21 inches × 2.54 = 53.34 cm.
See also: How to convert 21 cm to inches.