Menstrual Period Calculator

Free menstrual cycle calculator. Enter your last period date and cycle length to predict your next period and track future cycle dates. Use our free calculator

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Next Period hesaplanacak
Period 2 hesaplanacak
Period 3 hesaplanacak
Period 4 hesaplanacak

How to Predict Your Next Period

Menstrual cycles are counted from the first day of one period to the first day of the next. While the average cycle is 28 days, a normal cycle ranges from 21 to 35 days. Tracking your cycle helps you plan, recognize patterns, and detect irregularities.

What This Calculator Shows

  • Predicted start date of your next period
  • Next 6 months of predicted period dates
  • Estimated cycle phase for any date
  • Fertile window and estimated ovulation date

Menstrual Cycle Phases

PhaseDays (28-day cycle)What Happens
Menstrual1–5Uterine lining sheds
Follicular1–13Follicle develops, estrogen rises
Ovulatory14Egg released
Luteal15–28Progesterone rises, uterus prepares

Factors That Affect Cycle Regularity

  • Stress and major life changes
  • Significant weight changes
  • Intense exercise or changes in activity level
  • Hormonal contraceptives
  • PCOS, thyroid disorders, and other health conditions

When to See a Doctor

Consult a healthcare provider if: periods are consistently longer than 7 days, bleeding is extremely heavy (soaking a pad every hour), cycles are consistently shorter than 21 or longer than 35 days, or you miss 3 or more consecutive periods.

How to Use This Calculator

Using our calculator is simple: enter the required values into the input fields and click the calculate button. Results are displayed instantly on screen. You can adjust the values and recalculate to compare different scenarios and find the best option for your situation.

Frequently Asked Questions

QuestionAnswer
How accurate are the results?We use standard formulas and up-to-date 2025 rates. Individual circumstances may vary slightly.
Is this calculator free?Yes, completely free and no registration required.
What should I do for exact figures?For precise information, consult a relevant professional or official authority.
Does it work on mobile devices?Yes, it works seamlessly on all devices and screen sizes.

Important Notes

This calculator is provided for informational purposes only. For legal, financial, or medical decisions, always seek advice from qualified professionals. Calculation results do not constitute official documents. Legislative changes may affect results; please visit the relevant official website for the most up-to-date information. Our calculators are regularly updated to reflect current regulations and rates.

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Frequently Asked Questions

Predictions are estimates based on a regular cycle. Stress, illness, weight changes, and hormonal factors can shift your period by several days.
A normal cycle is 21-35 days, with most women averaging 28 days. Period duration of 2-7 days is typical.
Tracking helps identify irregular cycles, predict upcoming periods for planning, and provide useful information for healthcare providers.