Free · Health · Pregnancy & Cycle
Period Calculator
Project upcoming period and ovulation dates from a typical cycle and period length.
- Checked formula
- Private in your browser
- No signup
Result
Your calculation
- Next estimated period
- Monday, August 17, 2026 to Friday, August 21, 2026
- Following starts
- Monday, September 14, 2026; Monday, October 12, 2026; Monday, November 9, 2026
- Estimated next ovulation
- Monday, August 3, 2026
Calendar projections are less reliable with irregular cycles and do not confirm ovulation.
How to use this calculator
- Enter current measurements as accurately as practical.
- Calculate to see the estimate, range, and method details.
- Use the result as context, and discuss health decisions with a qualified clinician.
Use the result with context
Health results are educational estimates, not a diagnosis or treatment recommendation. A qualified clinician can interpret measurements in the context of your health.