One semester hour equals 1.5 quarter hours or 1 quarter hour equals .6667 semester hours. To convert semester hours into quarter hours divide the quarter credit hours by 1.5 or multiply the semester credit hours by .6667. To convert quarter hours into semester hours multiply the semester hours by 1.5. Typical graduation requirements are 192 quarter hours under a quarter system and 128 semester units under a semester system. 1  192 quarter credits divided by 1.5 = 128 semester credits.