Volume (amt of space occupied by matter)
in m3(SI   units) ;
 more conveniently liters (1 L = 1 dm3)
or milliliters (1 mL = 1 cm3)
1 gallon = 4 qts; 1 qt = 2 pts = 32 fluid oz
(4 cups = 1 qt)
1 qt = 0.946 L  (1L = 1.06 qt);
   1 gal = 3.78 L