When your last period was late, do u count from the day it came on or the day it was suppose to come on...?

Question

to see when the next one will come on?

Answer 1

i count from when i was suppose to have one.

it's easier.  

Answer 2

Always count from the day it come cause our period don't come on the same date every month.

Answer 3

i count from the day it came which makes it accurate for next time.