Period Calculator
Predict the dates of your next 6 periods based on your last period date and average cycle length.
How to Use the Period Calculator
Predict the dates of your next 6 periods based on your last period date and average cycle length. Enter your information in the form above and get instant results.
Medical Disclaimer: This tool is for informational purposes only. Always consult your healthcare provider for medical advice.
Frequently Asked Questions
How are future periods predicted?
By adding your average cycle length (default 28 days) to the first day of your last period, repeatedly for upcoming months.
Why are my predictions off?
Cycle length varies due to stress, illness, weight changes, and other factors. This tool provides estimates based on your average cycle.
What is a normal cycle length?
A typical menstrual cycle is 21–35 days. The average is 28 days, but variations are completely normal.