Enter the first day of your last period and your cycle length to project upcoming dates.
Fill in your details and press calculate — your result will appear here.
Formula and method
Each cycle starts one cycle length after the previous one. A period of N days beginning on day one ends on day N.
Formula used
Projected cycle starts at LMP + n x cycle length
Assumptions and limits
- The projection assumes a regular cycle. Month-to-month variation is normal.
Scientific sources
American College of Obstetricians and Gynecologists. “Committee Opinion No. 651: Menstruation in Girls and Adolescents.” Obstet Gynecol. 2015;126(6):e143-e146.