Period Calculator
This Period Calculator helps you predict your next menstrual period, average cycle length, and upcoming period dates based on the first day of your last period.
Most menstrual cycles range between 21 and 35 days.
Period Prediction
Next Period Date
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Cycle Length
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Next 3 Periods
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What Is a Menstrual Cycle?
The menstrual cycle is a monthly hormonal process that prepares the body for pregnancy. It begins on the first day of menstruation and ends the day before the next period starts.
Phases of the Menstrual Cycle
- Menstrual Phase: Shedding of the uterine lining
- Follicular Phase: Egg preparation
- Ovulation: Release of an egg
- Luteal Phase: Body prepares for pregnancy
How Period Dates Are Calculated
Period calculators estimate future periods by adding your average cycle length to the first day of your last period.
Next Period = LMP + Cycle Length
Why Track Your Period?
- Understand cycle regularity
- Plan activities and travel
- Track ovulation and fertility
- Identify irregular patterns early
Frequently Asked Questions
Period calculators provide estimates. Stress, illness, and hormonal
changes can affect cycle timing.
A normal menstrual cycle typically ranges from 21 to 35 days in adults.
Yes. Age, lifestyle, stress, and medical conditions can cause cycle
length variations.
If periods are consistently irregular, very painful, or absent,
consulting a healthcare provider is recommended.