Calculate and predict your next period dates based on your menstrual cycle. Track your cycle length, period duration, and plan ahead with accurate predictions for your upcoming periods.
Typical range: 21-35 days
Typical range: 2-7 days
Your menstrual cycle is the monthly hormonal cycle that prepares your body for pregnancy. Understanding your cycle helps you predict periods, identify fertile windows, and recognize any irregularities that may need medical attention.
A normal menstrual cycle ranges from 21 to 35 days, with the average being 28 days. Your cycle is counted from the first day of one period to the first day of the next. Period duration typically lasts 2-7 days, with 3-5 days being most common.
Your menstrual cycle consists of four main phases:
It's normal for cycle length to vary by a few days from month to month. Factors like stress, illness, travel, and lifestyle changes can affect your cycle. However, consistently irregular cycles may indicate an underlying health issue.
This calculator uses your menstrual cycle history to predict future period dates. Here's how it calculates your next periods:
Enter the first day of your last menstrual period. This is day 1 of your current cycle and serves as the starting point for all calculations.
Input your typical cycle length (21-35 days). If you're unsure, track at least 3 cycles and calculate the average. Most women have cycles between 26-32 days.
Enter how many days your period typically lasts (2-7 days). This helps calculate both the start and end dates of your upcoming periods.
The calculator predicts your next several periods by adding your cycle length to the last period date. It shows both start and end dates for easy planning.
Accurate cycle tracking helps you understand your body's patterns and identify any changes that may need attention. Here are effective tracking methods:
Mark the first day of each period on a calendar. After tracking 3-6 cycles, you can calculate your average cycle length and identify patterns. This simple method works well for regular cycles.
Digital apps automatically calculate cycle length, predict periods, and track symptoms. Many offer additional features like fertility tracking, mood logging, and health insights.
Record symptoms like cramps, mood changes, flow intensity, and PMS symptoms. This helps identify patterns and can be valuable information for healthcare providers.
Track your flow intensity (light, moderate, heavy) each day. Changes in flow patterns can indicate hormonal shifts or health issues that may need medical evaluation.
Basal body temperature rises slightly after ovulation. Daily temperature tracking can help confirm ovulation and identify cycle irregularities, especially useful for fertility awareness.
Cervical mucus changes throughout your cycle. Tracking these changes helps identify fertile days and provides insights into hormonal health and cycle regularity.
Cycles that vary by more than 7-9 days or are shorter than 21 days or longer than 35 days are considered irregular. Common causes include stress, PCOS, thyroid disorders, significant weight changes, and perimenopause.
Soaking through pads or tampons every 1-2 hours, periods lasting longer than 7 days, or passing large clots may indicate heavy bleeding. This can lead to anemia and may be caused by fibroids, polyps, or hormonal imbalances.
Missing three or more consecutive periods (excluding pregnancy) requires medical evaluation. Causes include excessive exercise, eating disorders, PCOS, premature ovarian failure, or pituitary disorders.
Severe cramps that interfere with daily activities may indicate endometriosis, fibroids, or pelvic inflammatory disease. While some cramping is normal, debilitating pain should be evaluated by a healthcare provider.
Physical and emotional symptoms occurring 1-2 weeks before your period are common. Severe symptoms that significantly impact quality of life may indicate PMDD (Premenstrual Dysphoric Disorder) and require treatment.
High stress levels can delay ovulation and cause irregular periods. Chronic stress affects the hypothalamus, which regulates reproductive hormones. Managing stress through relaxation techniques can help regulate your cycle.
Both being significantly underweight (BMI under 18.5) and overweight (BMI over 30) can affect menstrual regularity. Body fat produces estrogen, so extreme changes in weight can disrupt hormonal balance.
Moderate exercise supports menstrual health, but excessive high-intensity training can suppress ovulation and cause irregular or absent periods. This is common in athletes and is called exercise- induced amenorrhea.
Nutritional deficiencies, restrictive diets, or eating disorders can disrupt menstrual cycles. Adequate intake of iron, B vitamins, and healthy fats is essential for hormonal balance and regular periods.
Cycles are often irregular during puberty (first few years after menarche) and perimenopause (years before menopause). These transitions involve significant hormonal changes that affect cycle regularity.
Hormonal birth control, antidepressants, blood thinners, and other medications can affect cycle length, flow, and regularity. Always discuss menstrual changes with your healthcare provider when starting new medications.
PCOS, thyroid disorders, diabetes, endometriosis, and other conditions can cause irregular periods. Treating the underlying condition often helps regulate menstrual cycles.
Jet lag and disrupted sleep patterns from travel can temporarily affect your cycle. Your body's circadian rhythm influences reproductive hormones, so significant time zone changes may delay your period.
While cycle variations are normal, certain symptoms warrant medical evaluation:
If your previously regular cycle suddenly becomes irregular, or if your cycle length changes significantly (more than 7-9 days variation), consult a healthcare provider to rule out underlying conditions.
Debilitating cramps that prevent normal activities, bleeding that soaks through protection every 1-2 hours, or periods lasting more than 7 days require medical attention. These may indicate conditions like endometriosis or fibroids.
If you're not pregnant and miss three or more consecutive periods, or if you're under 15 and haven't started menstruating, seek medical evaluation. This could indicate hormonal imbalances or other health issues.
Spotting or bleeding between periods, especially if heavy or accompanied by pain, should be evaluated. While sometimes normal, it can indicate polyps, infections, or other conditions requiring treatment.
Period calculators are most accurate for women with regular cycles (varying by less than 3-4 days). For irregular cycles, predictions are less reliable. Tracking 3-6 cycles improves accuracy.
Yes, significant stress can delay ovulation and therefore delay your period. The hypothalamus, which regulates reproductive hormones, is sensitive to stress. Managing stress can help regulate your cycle.
Yes, variations of 2-3 days are normal. However, if your cycle regularly varies by more than 7-9 days, or if you notice sudden changes in your pattern, consult a healthcare provider.
Soaking through a pad or tampon every 1-2 hours, needing to change protection during the night, passing clots larger than a quarter, or periods lasting more than 7 days are signs of heavy bleeding that should be evaluated.
While unlikely, it's possible, especially if you have a short cycle or long period. Sperm can survive up to 5 days, so if you ovulate early, pregnancy is possible. Use contraception if you're trying to avoid pregnancy.