21 centimeters is equal to 8.26771654 inches.
To provide comparisons to known objects of similar size, here are a few examples:
1. The width of a standard sheet of paper is approximately 21.59 cm, which is slightly larger than 21 cm.
2. A standard smartphone has a length of around 14.7 cm, which is smaller than 21 cm.
3. The length of a dollar bill is 15.6 cm, which is also smaller than 21 cm.
4. The average length of a human hand from wrist to fingertip is about 19 cm, which is slightly smaller than 21 cm.
5. A standard pen is typically around 14 cm long, which is significantly smaller than 21 cm.
Overall, 21 cm is a little over 8 inches, making it larger than most small objects that fit in the palm of your hand, but smaller than most everyday items like books or laptops.