Period Calculator - حاسبة مجانية على الإنترنت

Knowing when your next periods are coming makes life dramatically easier - for travel planning, event scheduling, sports and fitness activities, sexual health, and basic preparation. This calculator predicts the next 6 menstrual cycles based on your last period and average cycle length, including expected ovulation dates and fertile windows. The forecast accuracy is high in the first 2-3 cycles (±2-3 days), decreasing in later cycles as natural variability accumulates.

Beyond convenience, period tracking is a vital women's health practice. Significant changes in cycle length, period duration, flow heaviness, or pain can signal hormonal imbalances, PCOS, thyroid issues, fibroids, endometriosis, or other conditions. Logging cycle dates and symptoms over 6-12 months gives your gynaecologist much better data than memory recall, and helps identify patterns that might otherwise be missed.

The calculator predicts each subsequent period as: Previous period start + Cycle length. Ovulation is computed as: Next period − 14 days (the luteal phase is biologically fixed at 12-14 days for most women, regardless of total cycle length). Fertile window spans 5 days before ovulation through 1 day after - the period when conception is biologically possible. This is the standard 'forward calendar' method used in fertility tracking apps worldwide.

Normal cycle length range is 21-35 days, with 28 days as the population average. Individual variation of ±3-5 days between cycles is normal and doesn't indicate any issue. Larger variation (±7+ days) or cycles consistently outside the 21-35 day range warrants gynaecological evaluation. PCOS commonly causes cycles of 40+ days; thyroid dysfunction can cause both short and long cycles; significant weight changes affect cycle regularity.

Calendar-based prediction has inherent limits. Late ovulation due to stress, illness or travel can shift the next period by 1-2 weeks. The fertile-window prediction is most accurate when combined with ovulation prediction kits (LH strips) or basal body temperature tracking. For pure conception or contraception planning, multi-method tracking is far more reliable than calendar alone.