Due date question!

Hello ladies!

Silly question, and I probably shouldn't worry about it but I wanted some opinions!

Every ultrasound I've gone to since the beginning of my pregnancy (3 appointments), the techs tell me my due date is August 26. But, at every check up with my doctor, he says my due date is September 1.

I'm just a little confused, it's not a huge difference in time, but I would like a more concrete answer and am not sure which date to take more seriously. So frustrating, haha.