🩸 How to Use the Period Day Calculator?
Understanding your menstrual cycle is essential for maintaining reproductive health, planning pregnancy and detecting irregularities. The Period Day Calculator helps estimate your next menstruation date based on the average length of your cycle and the date of your last period. It also optionally allows you to add the expected date directly to Google Calendar for easier personal tracking.
Calculate Your Period Date, Send to Google Calendar
🩸 Period Date Calculator
🔬 What Is a Menstrual Cycle?
The menstrual cycle is the monthly hormonal cycle a woman’s body goes through to prepare for a possible pregnancy. It begins on the first day of your period and ends the day before your next one. The average cycle lasts 28 days, but a range between 21 and 35 days is considered normal for adults.
🧮 How Is It Calculated?
This calculator uses two simple inputs:
- Last Menstrual Period (LMP) – the first day of your last bleeding.
- Average Cycle Length – the number of days between two periods.
The formula:
Next Period = Last Period Date + Average Cycle Length (in days)
For example, if your last period started on April 1st and your average cycle is 28 days, your next expected period is April 29th.
You may also enter your menstruation duration to better visualize your bleeding window.
🗓️ Bonus: Add to Google Calendar
Once calculated, the expected start date can be added directly to your Google Calendar with one click – helping you track symptoms, plan activities and stay prepared.
✅ Why Use This Tool?
- Plan ahead for travel, important events or health checkups.
- Improve fertility awareness for conception or contraception.
- Spot cycle irregularities and discuss them with a healthcare provider.