生理周期計算機

生理周期を分析し排卵日・妊娠可能期間を予測します

First day of last period

Average cycle length (days)

Estimated next period

2026年8月18日

Estimated ovulation

2026年8月4日

Estimated fertile window

2026年7月30日 – 2026年8月5日

This is a calendar estimate. Ovulation can vary from cycle to cycle and estimates are less reliable with irregular cycles, lactation, perimenopause, illness, or medicines. Do not use it for contraception, pregnancy confirmation, or infertility diagnosis.

Seek medical advice for a sudden cycle change, no period for 3 months when not pregnant, very heavy bleeding, fainting, or severe pelvic pain.