Forum user @Diazo made this wonderful little modlet a long time ago, but he hasn't been around since July, 2017. So I've adopted it
Landing Height
Found on the CKAN as Diazo's Landing Height Display (soon)
Found on Spacedock as Diazo's Landing Height
Caution: This mod only affects the altimeter display at the top of the screen, it does not change the altitude at which equipment operates. So if a parachute is set to open at 500m ASL, the parachute will still open at 500M ASL,