HP is determined mainly by job, then level.
The level has a very small effect on HP increase until 2nd job.
At 2nd job, warriors get huge HP bonuses and it grows exponentally, more for fighters than other warriors.
Other jobs, such as pirate, thief, bowman, and mage do not get as large an HP boost as warriors.
Mage gets NO HP boost at 1st job(or 2nd job:(), so mage has the least HP.

HP is NOT increased by STR, as the definition of STR (in Maple) says.
However, MP IS increased by INT, though.