Conversion units UE-5

I am trying to make terrain pieces as realistic as possible however, when I use the measurements that I get and put them in unreal the conversion rate for feet does not seem to work out . Is there a way of changing the units in unreal and where can I find it any help would be appreciated.

Thank you

Units are always metric - one UE unit = 1cm.
There is a table about half way down this page with some conversions to imperial: