As adjectives the difference between prepayable and preparable
is that prepayable is to be paid, or paid for, in advance while preparable is capable of being prepared.
prepayable
English
Adjective
(-)
To be paid, or paid for, in advance.
preparable
English
Adjective
(
-)
Capable of being prepared.
- Medicine preparable by art. — Boyle.
(
Webster 1913)