Who's ovulation predictor on this app is actually correct? And shouldn't it be that you are the most fertile on day 14?  I know this is not the case for everyone, as everyone has different cycles. However, I am in my fertile window now and today it gives me a 1.4% chance of conceiving, and yesterday it gave me 1.7%. Technically today (1.4%) would be the fourteenth day, the supposed most fertile day so why does it say yesterday was??