About this Calculator
Predicting your upcoming periods helps you plan your schedule, understand your body’s cycles, and monitor your reproductive health.
Formula & Calculations
Mathematical Formula
Next Period = Last Period + Cycle Length
Calculates future cycles and fertile windows for the next three months.
How to Calculate Step-by-Step
1
Input dates
Provide last cycle start date.
2
Project cycle
Add cycle length to project future starts.
How to Use & Best Practices
Enter your last period date, average cycle length, and period duration.
Frequently Asked Questions
What is a normal cycle length?
Typically between 21 and 35 days.