Pregnancy & Period Calculatorحاسبة الحمل والدورة الشهرية
Estimate your due date and current week, or track your next period and fertile window.قدّر موعد الولادة والأسبوع الحالي، أو تابع دورتك القادمة ونافذة الخصوبة.
Resultالنتيجة
How due dates and cycle estimates are calculated
كيف تُحسب مواعيد الولادة وتقديرات الدورة؟
The due-date estimator uses Naegele's rule, the standard obstetric method: add 280 days (40 weeks) to the first day of your last menstrual period, assuming a textbook 28-day cycle where ovulation happens around day 14. If you'd rather calculate from a known conception date instead, the tool adds 266 days (38 weeks), which is the average length of pregnancy counted from ovulation/fertilization rather than the last period.
Your current week and trimester are derived from how many days have passed since the (assumed) start of your cycle. Weeks 1-13 make up the first trimester, 14-26 the second, and 27 onward the third — though many clinicians define the exact cutoffs slightly differently. Because this method assumes a standard 28-day cycle, it will be less accurate if your cycles run consistently longer or shorter; an early ultrasound dating scan remains the most reliable way to confirm gestational age and due date.
The period tracker works on a simpler principle: your next period is estimated by adding your typical cycle length to the first day of your last one, ovulation is placed roughly 14 days before that, and the fertile window spans about five days before ovulation through one day after, reflecting sperm survival time and the egg's short viability window. Cycles naturally vary month to month due to stress, illness, travel, and hormonal changes, so treat these as planning estimates rather than guarantees — and if you're trying to conceive or avoid pregnancy, combine this with other tracking methods or medical guidance rather than relying on dates alone.