You make a standing long jump.
This means you jump from your current position to a new position on the x-axis.
This is calculated:
Creature Base Size + ( Body / 2)
You eye the jagged chasm below, its dark maw studded with glinting spikes. The rocky ledge ahead, rough and uneven, beckons. Dust swirls faintly, the gap wide, daring your bold leap to clear it.