Period & Ovulation Calculator - ToolVerse Free Online Menstrual & Fertile Window Predictor

Period & Ovulation Calculator — Free Cycle & Fertile Window Predictor

Last period start date (YYYY-MM-DD)

Average cycle (days)

Period length (days)

Number of cycles to predict

Ovulation & fertile-window rule

Default assumption: Ovulation ≈ 14 days before the next period. Fertile window = from 5 days before ovulation to 1 day after ovulation (~7 days).