Is it normal for the HCG level to go from 1200 1640 in 2 days and if so how far along are you?

Yes, it is normal for the hCG level to increase rapidly in early pregnancy. The hCG level typically doubles every 2-3 days in the first few weeks of pregnancy. If your hCG level went from 1200 to 1640 in 2 days, it is likely that you are approximately 4-5 weeks pregnant. However, it is important to note that hCG levels can vary widely between individuals, and the exact gestational age can only be determined by an ultrasound.