Please tell me what you think ❤

Okay guys so I never use ovulation kits or what not just because their sort of pricey. So I usually base my ovulation day from an app called "My Calander". My calendar says my fertile window was from the 15th- 21st. Ovulation day being the 20th. HOWEVER glow said my fertile window started on the 20th and ends the 26th.

WHICH IS CORRECT?! I'm so confused and am desperate for my rainbow baby after miscarriage.

My latest period was June 7th-10th

Period length is 4 days

Cycle length is 27 days

Average luteal phase length is 14 days.