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Period Calculator

Track Your Cycle & Plan Ahead

Enter your cycle details to predict your next period and fertile days.

Days from start of one period to the next.
How many days your bleeding usually lasts.

Your Cycle Prediction

Enter your details to see your next period start date and cycle milestones.

Understanding Your Menstrual Cycle

What is a Menstrual Cycle?

The menstrual cycle is a series of natural changes in hormone production and the structures of the uterus and ovaries of the female reproductive system that make pregnancy possible. The cycle is counted from the first day of one period to the first day of the next.

While the average cycle is 28 days, it is perfectly normal for cycles to range from 21 to 35 days in adults and up to 45 days in teens.

The Four Phases of the Cycle

  1. Menstrual Phase: This is your period. The thickened lining of the uterus (endometrium) is shed through the vagina.
  2. Follicular Phase: Starts on the first day of your period and ends with ovulation. The pituitary gland releases FSH (follicle-stimulating hormone) to stimulate the ovaries to produce follicles.
  3. Ovulation Phase: The release of a mature egg from the surface of the ovary. This usually happens mid-cycle.
  4. Luteal Phase: The time between ovulation and the start of your next period. The body prepares for a possible pregnancy by producing progesterone.

Why Track Your Period?

Tracking your cycle is about more than just knowing when your next period will arrive. It can help you:

  • Identify Patterns: Understand your body's unique rhythm and recognize when something is "off."
  • Manage Symptoms: Predict when PMS symptoms like bloating, mood swings, or cramps might occur.
  • Plan for Life: Schedule vacations, weddings, or athletic events with confidence.
  • Fertility Awareness: Know your most fertile days if you are trying to conceive (or avoid pregnancy).
  • Health Monitoring: Irregular cycles can sometimes be a sign of underlying health issues like PCOS or thyroid disorders.

What is Considered an "Irregular" Period?

A period is generally considered irregular if:

  • The time between periods keeps changing.
  • You lose more or less blood than usual.
  • The number of days that the period lasts varies a lot.

Occasional irregularities are common due to stress, travel, or illness. However, if your periods are consistently irregular, it's a good idea to speak with a healthcare provider.

Tips for a Healthy Cycle

  • Balanced Nutrition: Ensure you're getting enough iron, especially during your period.
  • Regular Exercise: Can help reduce cramps and improve mood.
  • Stress Management: High stress can delay or even stop your period.
  • Adequate Sleep: Sleep deprivation can disrupt the hormones that regulate your cycle.

Frequently Asked Questions

Most periods last between 3 and 7 days. If your period consistently lasts longer than 8 days, you should consult a doctor.

Yes. Stress increases cortisol, which can interfere with the hypothalamus—the part of the brain that regulates your menstrual cycle.

Mild to moderate cramping is normal as the uterus contracts to shed its lining. However, severe pain that interferes with daily activities (dysmenorrhea) should be evaluated by a professional.

Cycle Tips

  • Keep a period diary or use an app.
  • Stay hydrated to reduce bloating.
  • Use a heating pad for cramps.
  • Eat iron-rich foods like spinach.
  • Practice self-care during PMS.

Important Links

All Health Calculators Ovulation Calculator Pregnancy Due Date BMI Calculator
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Menstrual Health:

Medical Disclaimer

This Period Calculator provides estimates based on average cycle data. It is not a substitute for professional medical advice or a diagnostic tool. If you experience severe pain, extremely heavy bleeding, or highly irregular cycles, please consult a healthcare professional.