I Am A Number; When H Is Added, I Become Bottom Of The Feet | with Answer

 Can you find out the Number and the word?

WHO AM I ?

I am a number; when H is added, I become the bottom of the feet to the top of the head.

Who am I ?

ANSWER

Number is "EIGHT"

When H is added 'EIGHT' becomes 'HEIGHT', which is bottom of the feet to the top of the head.