The easiest way to figure it out is to take the number of weeks and divide by 4.35 because the number of dais in a month varies.
Your First Trimester:
1st Month = Weeks 1,2,3,4
2nd Month = Weeks 5,6,7,8
3rd Month = Weeks 9,10,11,12,13
Your Second Trimester:
4th Month = Wks 14,15,16,17
5th Month = Wks 18,19,20,21
6th Month = Wks 22,23,24,25,26
Your Third Trimester:
7th Month = Wks 27,28,29,30
8th Month = Wks 31,32,33,34,35
9th month = Wks 36,37,38,39,40
Theres 4 weeks in a month. Just count up by fours
14 weeks = 3 months two weeks 16 weeks= four months 20 weeks = 5 months.
16 weeks I believe when you'll be in your 4th month.
When will I be consider four months ?