How Do U Calculate Your Luteal PhaseadminApril 28, 2026Calculators Calculate Your Luteal Phase Date of Last Menstrual Period: Average Length of Menstrual Cycle: 28 days 29 days 30 days 31 days 32 days 33 days 34 days 35 days Calculate World Health Organization – Menstrual Health Mayo Clinic – Menstrual Cycle