Calculating DPO

Krystal • Tue, Dec 13

What is the most accurate way to measure DPO?

This was my first month using the ClearBlue Advanced OPK. I peaked and had a solid smiley face on Saturday Dec. 3, but this app sent me an alert on Monday Dec. 5 that I was ovulating. I'm just confused on what day to start counting from and I'm anxious to see if we will be getting a rainbow baby for Christmas this year.