With this online calculator you can convert grams to drops.
Formula:
N = M / M1
N - number of drops
M - mass
M1 - mass of one drop
Pharmaceutical measure of a drop:
For aqueous solutions 1 drop = 0.05 grams (20 drops is 1 gram).
For alcohol solutions 1 drop = 0.025 grams (20 drops is 0.5 gram).
Drop is the amount of liquid that takes a round shape due to the cohesion of its particles.