Why are my apps giving different pregnancy dates

Question

Glow is saying 4 weeks 2 days and pregnancy+ is saying 4 weeks 1 day, same date for last period (nov 27). I understand both, just wondering which counting method doctors go by. My last period was on a Friday, so technically today being Saturday marks 4 + 1. Yet glow actually counts period day 1 as day 1 of pregnancy which makes it a day ahead

Answer

Glow has always been a day ahead, I go off of pregnancy+ because that’s the same date my doctors have given me too

Answer

Day one of your period is technically day one of pregnancy as it’s the entire cycle, conception and gestation.

Answer

I've been wondering the same. I uninstalled a few apps that I liked less so I could narrow down the dates to save on stress😂😂.
I used the maya app to track my period and sex days for months. It's been good to me because it's taken me years to get pregnant again. 
I actually made a post on this app or another app about the accuracy of my due date for multiple reasons so it's cool I find this post and someone else who can relate. Are you a ftm?

Why are my apps giving different pregnancy dates

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