This app always seems to he way off with that... it definetely has some glitched. Ultrasounds are really off as well but if you Google it Wil give you the same number across most websites and your ultrasounds will line up with that number at this point. Around 30 weeks or so they start varying in size
This app is just an estimate of what *could* be the weight of your baby at this gestational age. The weight can vary by ounces or even pounds.