How far along am I?

Li

My Lmp was June 19th, both the Ovia <a href="https://play.google.com/store/apps/details?id=com.glow.android.nurture">pregnancy app</a> and What to Expect app have me at exactly 5 weeks today but this app says 5 weeks and 1 day. I haven’t had an ultrasound yet so I’ll obviously eventually go with what my doctor says but any idea why this app would put me a day ahead?