Let's not forget mixing that syrup or concentrate in small quantities. (Different standards define drops as opposed to exacting w/ a syringe in mL, and to make it more interesting, all drops are not the same size.)

Metric Drop = 1/20 mL
1 Tsp = 5 mL (120 drops)
1 Tbsp. = 15 mL (.3333 Tbsp)

If you're in the U.S., and want further confusion:
The U.S. drop is defined as 1/60 of a teaspoon or 1/360 of a U.S. fluid ounce (approximately 82 ěL).
An alternate definition of the U.S. drop is 1/76 of a teaspoon or 1/456 US fl oz (approximately 65 ěL).