How big is an inch? Like compared to fingers or centimetres?

I am considering donating my hair, and i've done research and i've found out that your quill has to be atleast 10inches to donate, and that 14 inches is just what the doctor ordered.so how big is ten inches?? 2.5 cm = one inch..
ten inches = 25 cm.
good for you for donating!
.. do you own a ruler?
if not.. hmm... its intricate to tell but its going on for...
the size of your... | and \ button maybe a smidge bigger.. haha.. below backspace.. thats a standard keyboard approaching at school...
thats bout an inch.. or shift to school/ longs/ walmart/ target and ask for a ruler.. its 12 inches..

edit.
the woman that talks almost the shoe thing is wrong..
i wear a size 4-5 and my food is not 4-5 inches long. at adjectives.
well ur foot is down ur wrist to elbow. so say you wear a size 9 shoe...wrist to elbow would be roughly 9 inches.