It will show just how big a rise you’ve had (8)
I believe the answer is:
altitude
'it will show just how big a rise you've had' is the definition.
The definition suggests a singular noun which matches the answer.
This is the entire clue.
Can you help me to learn more?
(Other definitions for altitude that I've seen before include "Height above sea-level" , "Height, elevation" , "Angular distance above the horizon" , "Loftiness" , "Elevation above sea-level" .)