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Period Tracker predicts your next 4 period start dates, ovulation days, and 6-day fertile windows using standard cycle length calculations (ovulation ≈ cycleLength − 14 days before next period), and lets you log daily symptoms and flow.
Period Tracker is a high-performance utility designed to help users streamline their workflow. Built with modern web technologies, it ensures fast processing times and high-quality outputs directly in your browser.
Ovulation day estimated as cycleStartDate + (cycleLength − 14). Fertile window = ovulation − 5 days through ovulation + 1 day (accounting for sperm survival up to 5 days and egg viability 12–24h). Cycle phases use standard luteal phase of 14 days.
Predictions are estimates based on your average cycle length. Cycles vary due to stress, illness, and hormones.
The fertile window is roughly 5 days before ovulation plus ovulation day — about 6 days total.