Weeks calculator confusion

[Lovethatjourneyforme]

Hi all! Hoping someone can explain this to me cos I'm just confused...
I found out I was pregnant a few days ago. 1st day of my LMP was 01/09/2020, which by my reckoning and 1 app that used, makes me 5 weeks and a day. So why is every other calculator online telling me I'm 4 weeks 4 days? I've also tried going by conception date, in case it's because of cycle length, still says 4 weeks 4 days?

Confused how it's got to that number. And disappointed that I'm less that I thought!

@Lovethatjourneyforme
Find a website that bases it on the first day of your last period, as that's what NHS go by! X

@Lovethatjourneyforme
I would love clarification too! My LMP was the 30/08/20 so my app calculated that I'm 5+3! But my Flo app, that I used to track my periods and then log the pregnancy says I'm 6+3?! ... boggling my brain! I have a scan booked for the 18th October which by the time I should at least be 7 weeks... I hope. X

The standard human pregnancy is anything between 37 and 43 weeks. The first 2 weeks being counted are before conception takes place. It’s such an inexact science (apart from dating scans) that it really isn’t worth being worried about a few days. It’s a marathon from this point!

So I was very confused about this as well. It looks like some calculate the week starting with the first day of your last period as 'Week 1' while others calculate it as 'Week 0' (with the next week then being 'Week 1').

I kinda think the Flo app is wrong, as all of the 'medical' calculators I've used are dating me one week less. However, I haven't figured out a reason for this discrepancy at all!

The NHS calculator is the best to go off as that's what they'll use when booking you in, once you get your 12 week scan they'll be able to provide you with a due date based on measurements. I was 2 days ahead of the NHS date as my cycles were 26 days rather than 28 days which is what the initial date is based off x

@Stef92 yeah I looked on the NHS app and it's saying I'm 5 weeks, Flo must be calculating week 0 as week 1.

It will be because you might not ovulate at day 14 which is the time LMP is most accurate. If you ovulate later you're not as far along as counting from LMP.

I tend to count ovulation day as being 2 weeks pregnant and count forwards from that.

That's possibly why yours is different based on cycle length and likely ovulation and not just LMP.

Also the NHS calculator does not just go off LMP but cycle length too so that will be most accurate for now see what that says and go off that

Flo has a setting for completed or current weeks to be shown. Change it to completed.

The setting is under the pic of the embryo.

@Lovethatjourneyforme
I would go by the 4weeks 4 days to be Conservative.
If you do book an early scan better to be ahead than what you thought than behind...

I have 32 days cycle and ovulate on day 18 and my inital EDD was based on LMP. So further along than if i went by conception. Which didn't make sense as i knew i had not ovulated before day 18.
However at my 12w scan baby was measuring bang on with my LMP so somehow outgrew herself or whatever but i kept the same date.

In short until your dating 12w scan, i wouldn't worry about trying to date accurately.

The flo app counts how many weeks you currently are whereas most other apps count how many weeks have passed... Think of it like birthdays. You say the baby is one year old at the end of the first year, so you are 4 weeks pregnant at the end of 4 weeks. You'd say the same baby was in its second year of life, like you'd say you were in week 5 of pregnancy. You can change the flo settings to make it into weeks that have passed rather than current week... If that makes sense. Weeks that have passed is the most common way of saying how many weeks you are. I'll be 11 weeks tomorrow, but entering my 12th week of pregnancy

@Welliedays ahhh I get it now, I've amended the app to completed. Thanks. X

@Sexnotgender that's great thank you x

Thanks for your replies everyone, much appreciated ☺️

I know it's only a few days difference and it seems silly, it was just that my 1st pregnancy ended in MC at 11 weeks and I'm very anxious to make it to the 2nd trimester this time... Just seems such a long way off!