Confused..

Amanda β€’ 5 years of love 😍 teacher πŸ‘©πŸ»β€πŸ« dog mom 🐾 mommy to Ava 9/5 πŸ‘ΆπŸΌ

So I have a few <a href="https://play.google.com/store/apps/details?id=com.glow.android.nurture">pregnancy apps</a>. <a href="https://play.google.com/store/apps/details?id=com.glow.android.nurture">Nurture</a>, what to expect and pregnancy+ says 6w5d, but Glow and Babycenter says 6w6d.. what the heck? Which one do you guys follow?