Gah, how pregnant am I? Can't count for toffee

[squasages]

Please someone, lend me your maths brain! Am totally confused.

I am due on 26th Oct but have never been able to count so just went with how far along they said I was at my first scan. Recorded it in my diary and have been counting faithfully - this would make me 16+5.

However, just looked at the bbc pregnancy calendar and it says I am only 15+2 - over a week's difference!

I'm totally baffled as I cannot overstate the crapness of my ability to do even basic calculations. Got my anomaly scan coming up for what I thought would be 20+2

I due 12/10, and 19 weeks on Tuesday so you're 17 weeks on Tuesday!!

The bbc calendar seems to be wrong - I'm 20 weeks today, due 3rd Oct and the beeb calendar says I'm only 19... There are other calendars around which will calculate where you are and give you info about your week. It seems better to put your due date in - some seem to calculate a couple of days difference - but bbc one is just wrong!!

i use this website to work out how far along i am.

I'm due on 29th Oct and i turned 16 weeks on friday.
So You were 16 weeks last Tuesday - 17 weeks tomorrow.

Its not just you. My boss looked very suspicious when i couldn't remember how far gone i was when he asked me last week.