Ovulation Calculatorのしくみ
The calculation follows the standard scientific model: ovulation typically occurs cycle length − luteal phase days after the first day of your last period. The luteal phase (time between ovulation and the next period) is relatively constant for most women at 12–16 days, typically 14 days. The fertile window starts 5 days before ovulation (sperm survive up to 5 days) and ends 1 day after (egg viable for ~12–24 hours). Formulas: Ovulation = period + (cycle length − luteal phase) · Fertile window = ovulation − 5 to ovulation + 1 · Next period = period + cycle length.