How many weeks pregnant?

Why does the glow app say that I am 3 weeks and 6 days pregnant, but every other site I calculate it on says I am 4 weeks 5 days? This includes the P Tracker app that I have been using for two years and has longer records of my cycles.

Glow Resources

Let’s Glow

Glow is here for you on your path to pregnancy

Glow helps you navigate your fertility journey with smart tools, personalized insights, and guidance from medical experts who understand what matters most.

25+ million

Users

4.8 stars

200k+ app ratings

20+

Medical advisors