Period Calculator

Free calculate menstrual period and cycle. This is an educational tool only - always consult a healthcare provider.

Cycle Information

Typical: 21-35 days

Results

Enter cycle information to calculate period dates

About Menstrual Cycle

  • • Average cycle: 28 days
  • • Period: 3-7 days
  • • Ovulation: ~Day 14 (28-day cycle)
  • • Fertile window: 5 days before ovulation
  • • Cycle length varies per person