你要去哪里用：where are you going？ 还是where are you going

是Where are you going？

“where are you going to”不代表什么意思，因为这句话没说完，除非是“where are you going to go?"那就代表同样的意思：你要去哪里。"where are you going to”里面含有的are going to是表示将来时的句式。