High Jump

Source: D&D 5.2 SRD Rules Glossary

When you make a High Jump, you leap into the air a number of feet equal to 3 plus your Strength modifier (minimum of 0 feet) if you move at least 10 feet on foot immediately before the jump. When you make a standing High Jump, you can jump only half that distance. Either way, each foot of the jump costs a foot of movement.

You can extend your arms half your height above yourself during the jump. Thus, you can reach a distance equal to the height of the jump plus 1 1/2 times your height.